Twist-stacked black phosphorus for wide-spectral chiral photodetection

Domain: physics
Published: 2026-01-17
Editorial outcome: major_revision

Abstract
On-chip integrable circularly polarized light (CPL) detectors hold significant potential for applications in optical communications, bioimaging, quantum information, and intelligent sensing, enabling chip-scale chiral light detection and information processing. However, current developments in materials and structural designs struggle to achieve wide-spectral detection capability while maintaining high circular polarization discrimination. This limitation significantly constrains the practical applicability of such detectors in complex environments and object detection scenarios. Herein, we propose a CPL detector based on a twist-stacked black phosphorus (b-p) system. By utilizing twisted b-p as an artificially constructed unit with chiral response and designing a symmetry-stacked sandwich structure in space, we achieve bipolar circular polarization detection and imaging across a wide wavelength range (from visible light to mid-infrared), with peak responsivity reaching 0.1 A/W. This design demonstrates both theoretically and experimentally the feasibility of utilizing a twist-stacked b-p system for wide-spectral CPL detection. This advancement offers valuable insights for addressing the bottlenecks in chip-integrated CPL detection technology.

Introduction
Circularly polarized light (CPL) detection is widely used for various applications in sensing and imaging1,2. The two-dimensional (2D) design (2D materials and 2D structures) for CPL detection enables the integration of traditional CPL detection schemes, which require spatial degrees of freedom, into compact on-chip detectors, offering limitless possibilities for chip-level CPL detection technology. Currently, the mainstream methods for designing CPL detectors can be divided into two major categories (Fig. 1a): the first approach relies on materials with chiral molecular structures to achieve CPL detectors with high responsivity3–12. However, their responsive wavelength is determined by the bandgap of the chiral materials, usually limited to short wavelengths ranging from ultraviolet to near-infrared (below 1000 nm). Importantly, these types of devices are often susceptible to interference from unpolarized light and linearly polarized light. The second widely adopted approach employs artificial plasmonic structures, which can offer greater circular dichroism, with the wavelength tunable to arbitrary bands13–18. However, this method is confronted with inherent limitations: it can only respond to CPL at the designed specific wavelength, making it ineffective for a broad range of CPL wavelengths. Therefore, these methods primarily focus on enhancing circular dichroism and fall short of meeting the demands for wide-spectral detection under complex scenarios.

Among the many challenges encountered in the development of CPL detection, the key difficulty lies in achieving broadband detection capability while maintaining high circular polarization discrimination and high responsivity. As a promising infrared photodetection material, 2D black phosphorus (b-p) exhibits exceptional properties, including an ultra-broad response spectrum, high carrier mobility, polarization sensitivity, and compatibility with silicon-based technology19,20. However, due to its inherently achiral structure, the development of b-p in photodetection has thus far been restricted to linear polarization detection21–27. Consequently, there is a lack of design strategies that enable b-p to be utilized for CPL detection, which is essential for addressing the diverse demands of CPL detection.

Herein, we propose a CPL detector based on a twist-stacked b-p system. By utilizing twisted b-p as an artificially constructed chiral response unit and designing a symmetry-stacked sandwich structure in space, we achieve bipolar circular polarization detection across a wide wavelength range (from visible light to mid-infrared), with peak responsivity reaching 0.1 A/W. This design demonstrates both theoretically and experimentally the feasibility of utilizing a twist-stacked b-p system for on-chip CPL detection. It achieves a breakthrough in overcoming the long-standing challenges associated with the operational wavelength range of CPL detection, while also exhibiting high responsivity, immunity to non-CPL components, and a high CPL discrimination rate. This advancement offers valuable insights for addressing the bottlenecks in chip-integrated CPL detection technology.

Results
Mechanism of twist-stacked black phosphorus CPL detector
Due to the anisotropic optical absorption properties of b-p (left subfigure of Fig. 1b), numerous studies have reported the design of b-p as a photodetector sensitive to linearly polarized light21–27. However, none have successfully achieved the detection of more complex polarization information, such as CPL. The controlled twisting and stacking of multilayer 2D materials at specific angles has emerged as a promising strategy for introducing optical chirality into non-chiral systems28. However, such an approach has largely remained at the level of optical characterization, and it remains challenging to achieve chiral-light detection through complex photoelectric conversion processes. Here, twist b-p structures can break mirror symmetry to some extent, providing a platform for responding to CPL (right subfigure of Fig. 1b)29–32. The basic unit of this design consists of two twisted, anisotropic b-p layers with different thicknesses, producing a chiral response to CPL (Fig. 2a). By controlling the twist angle, we can construct chiral units that respond to CPL, referred to as the twist 1 and twist 2, respectively, as shown in the left subfigure of Fig. 2b. However, relying solely on chiral units for CPL detection poses several challenges: firstly, each part of the b-p in the chiral units also responds to linearly polarized light, inevitably introducing interference from linear polarization components, which results in a low discrimination ratio. Secondly, the chiral units generate relatively weak polarized photocurrents in response to CPL, limiting the detection capability of the device.

To solve these issues, we designed the chiral units in a vertically stacked sandwich structure, as shown in the middle subfigure of Fig. 2b. The twist-stacked system consists of a thicker middle-layer b-p and thinner top and bottom-layer b-p, twisted by angles φ1 and φ2, respectively. In the detection process, electrodes are connected to both ends of the top b-p and bottom b-p layers. Under left-handed circularly polarized (LCP) illumination, the circular photogalvanic effect (CPGE) is generated at both the twist unit 1 and twist unit 2 interfaces, producing a photocurrent that flows upward along the interlayer vertical direction. Since the currents are in the same direction, they combine, resulting in a larger photocurrent signal. In contrast, when the right-handed circularly polarized (RCP) light is incident, the CPGE at twist 1 and twist 2 generates a photocurrent flowing downward along the interlayer vertical direction, which also adds up. As a result, a reversed bipolar photocurrent signal is generated for CPL of opposite LCP and RCP. This reversed photocurrent significantly enhances the discrimination ratio of gph = 2|I_LCP - I_RCP| / |I_LCP + I_RCP|33, in which I_LCP and I_RCP respectively represent the photocurrent exhibited by the device under LCP and RCP illumination. The discrimination ratio can, theoretically, reach infinity if I_LCP = -I_RCP.

Additionally, due to the difference in work functions between the thicker (middle-layer) and thinner (top and bottom-layer) black phosphorus layers, symmetrically distributed homojunctions are formed in the vertical direction25,34–38. This symmetric homojunction design helps mitigate the photocurrent from linearly polarized (LP) components during detection, as illustrated in the right subfigure of Fig. 2b. This is because the photocurrent generated by LP light mainly arises from the separation of photogenerated carriers in each b-p layer under the influence of the built-in electric field of the homojunction. Therefore, the symmetric design of the homojunction leads to LP photocurrents flowing in opposite directions, which partially cancel each other out.

Specifically, as shown in Fig. 2c, when light passes through a quarter-wave plate (QWP) and illuminates the device, the twist 1 unit generates three components of photocurrent: CPL photocurrent at the interface and two LP photocurrents from the top b-p and middle b-p layers. Similarly, the twist 2 unit produces CPL photocurrent as well as LP photocurrents from the middle b-p and bottom b-p layers. The circularly polarized photocurrent arises from the CPGE generated by two twist units with the same twist angle direction, resulting in currents flowing in the same direction, which allows for their accumulation. The LP photocurrent is generated by the top b-p, middle b-p, and bottom b-p layers, which flow in opposite directions due to the influence of the symmetric potential distribution. The LP photocurrent from the middle b-p will be canceled out, and the LP components from the top b-p and bottom b-p are significantly weakened. Ultimately, this design greatly reduces the interference from LP components during circular polarization detection.

To explain the mechanism underlying the generation of the CPGE, we theoretically constructed two bilayer-twisted systems with twist angles φ~15° and 60°, and calculated their electronic structures, as shown in Fig. 2d, e39–42. In the case of a twist angle of ~15°, the bands are relatively flat along the Γ-Y high-symmetry path near the energy gap, with both the conduction band minimum and the valence band maximum at Γ. Under illumination, it is easy to excite charges near this position, providing a conduction current. We further analyzed the spatial distribution of the electronic states near the Γ point and found that part of the states at the conduction band minimum are distributed in the inter-layer regions, which can provide carrier conduction channels in the vertical inter-layer direction. The case of a twist angle of ~60° exhibits similar characteristics, especially that part of the electronic states at the conduction band minimum is also distributed in the inter-layer regions. The twist angle used here is not unique; we have also performed calculations for other angles (see Supplementary Table 1 and Supplementary Fig. 1–1 of Supplementary Note 1).

We theoretically derived the current density of the CPGE in the bilayer-twisted systems, and obtained the current density along the z-direction as (more details are provided in the Supplementary Figs. 1–2 of Supplementary Note 1):

J_CPGE = 2E_0^2 \gamma_zz sinθ (1)

where E_0 is the magnitude of the applied electric field, \gamma_ij is a second-rank tensor for the CPGE, and θ=2(QWP angle). This is consistent with the experimental results of the 180° QWP rotation cycle. The calculation indicates that under the incidence of LCP and RCP light, the chiral units generate CPGE-induced photocurrents in opposite directions, respectively. The superposition of the two chiral units significantly enhances the CPGE-induced photocurrent, which is consistent with the experimental observations43–45.

Circular polarization detection
Next, we experimentally investigated the circular polarization detection mechanism of the twist-stacked b-p device. Based on the calculation results, we fabricated a trilayer twist-stacked b-p device. The middle b-p and the top b-p form twist unit 1 with a twist angle of approximately 60°, while the middle b-p and the bottom b-p form twist unit 2 with a twist angle of approximately −15°, as shown in Fig. 3a. By performing near-infrared (1210 nm) reflective circular dichroism (RCD) measurements on trilayer twist-stacked b-p, we observed high RCD values in the overlapping region of the trilayer b-p, indicating a strong chiral response in this area, as shown in Fig. 3b. This is difficult to observe in bilayer-stacked devices (Supplementary Figs. 2–3 and 2–4 of Supplementary Note 2 provide more comprehensive testing information). Motivated by this prominent characteristic, we conducted photocurrent measurements under circularly polarized illumination. When we connected the electrodes to the top b-p layer and the bottom b-p layer for photocurrent mapping tests, we observed a clear generation of photocurrents with opposite polarities under RCP and LCP illumination in the overlapping region of the trilayer b-p. This observation is consistent with the theoretical calculations of CPEG.

Next, we explored the photocurrent patterns by connecting different layers of b-p to verify the responses of various twist units to CPL, as shown in Fig. 3d. When the electrodes were connected to the top b-p and middle b-p layers, corresponding to the twist unit 1 (top subfigure of Fig. 3d), the system exhibited a switchable photocurrent response to LCP and RCP with different magnitudes but the same polarity. This is attributed to significant interference from the linearly polarized response components of the top and middle b-p layers. Similarly, when the electrodes were connected to the middle b-p and bottom b-p layers (bottom subfigure of Fig. 3d), a similar effect was observed. Notably, in the configuration where the electrodes were connected to the top and bottom b-p layers (middle subfigure of Fig. 3d), the device demonstrated photocurrent responses with opposite polarities for different CPL. This indicates that the trilayer twist-stacked b-p system successfully suppresses the interference from the linearly polarized response components. The detailed physical processes and corresponding analyses are provided in Supplementary Fig. 2–1 and 2–2 of Supplementary Note 2.

Furthermore, we can analyze the contribution of each polarization response by testing the QWP angle-dependent photocurrents under 1.55 μm laser illumination, as shown in Fig. 3e. As previously analyzed, in the twist-stacked b-p system, bipolar detection of circularly polarized light can be achieved at the terminals of the top b-p and bottom b-p layers, showing opposite photocurrent polarities (positive and negative) for LCP and RCP, respectively. This overcomes the limitations of using the traditional discrimination ratio in chiral materials, enabling a more intuitive distinction between the two polarization states. In contrast, relying solely on adjacent b-p layers does not allow for bipolar detection, and the relationship between photocurrent and the QWP angle cannot be fitted by a standard sinusoidal curve due to significant interference from linear polarization components. To further investigate, we extracted Stokes parameters for the three curves, as shown in Fig. 3f. We can write the general expression for a polarization-dependent photoresponse: V_ph = R_0 \cdot S_0 + R_1 \cdot S_1 + R_2 \cdot S_2 + R_3 \cdot S_3, with the R_0,1,2,3 as the respective responsivities to the four Stokes parameters, S_0,1,2,3. Note that S_0, S_1, S_2, and S_3 represent the intensity of light, two linearly polarized components, and the circularly polarized light component, respectively. As shown in Fig. 3f, in the configuration where the electrodes are connected to the top b-p and bottom b-p layers (middle subfigure of Fig. 3f), the proportion of linear polarization components (R_1 and R_2) is significantly smaller compared to the other two configurations (top and bottom subfigures of Fig. 3f). This indicates that the design can effectively reduce the interference from linear polarization components in circular polarization detection. More analysis can be found in the Fig. 2 and Figs. 2, 3 of Supplementary Note 2.

Wide-spectral response characteristics of the device
For the mainstream methods currently used for on-chip circular polarization detection, including chiral materials and metasurface-assisted approaches, challenges remain in achieving high circular polarization discrimination over a broad wavelength range. The design proposed in this work fills this gap by enabling CPL detection with a broad wavelength range, high responsivity, and high discrimination simultaneously.

The multilayered stacked structure offers multiple electrode configurations (Fig. 4a), allowing the device to operate in different modes to meet the detection requirements of specific scenarios. For example, the photovoltaic effect under zero bias can offer a high on-off ratio, while the photogating effect under applied gate voltage can provide enhanced responsivity. When the electrodes are connected on the intra-layer (C–D), the source-drain current of the device under different wavelength illumination (633 nm, 1550 nm and 2700 nm), all at the same power (50 μW), varies with the applied bias as shown in Fig. 4b. The device exhibits responsiveness across a broad spectrum, from visible to infrared light (see mid-infrared absorption and response measurements in Supplementary Fig. 3–1 of Supplementary Note 3), and as the bias increases, the photocurrent also increases, as depicted in the inset. The maximum responsivity can reach up to 0.1 A/W. Under extremely weak illumination (~1 μW) test conditions, the source-drain current response as a function of bias voltage for the interlayer connection (A–C) is shown in Fig. 4c. The interlayer exhibits clear junction-like photovoltaic characteristics, indicating the presence of homojunctions between the layers. In addition, depending on the connection method of different ports, the device can also demonstrate bipolar linear polarization detection capability, switchable dual operating modes and tunable circular polarization rule with fast temporal response characteristics, as shown in Supplementary Fig. 3–2—5 of Supplementary Note 3.

Blackbody detection, as a detection standard for practical applications, is used to demonstrate the infrared detection performance of photodetectors. This allows us to evaluate the responsivity of device to weak radiation across a broad spectral range43–45. Figure 4d presents the schematic diagram of the blackbody detection system. The blackbody source is Cisystems SR200N with an adjustable temperature (750 K–1000 K). The device was placed in front of the aperture with a fixed modulation frequency chopped by an optical chopper wheel. Under black-body radiation at different temperatures, the device can display stable photoelectric chopper signals, as shown in Fig. 4e. Furthermore, the relationship between the measured responsivity, equivalent noise power (NEP) and specific detectivity (D*) with temperature under blackbody radiation was obtained, as shown in Fig. 4f. It can be observed that this device exhibits high photoelectric responsiveness in the infrared spectrum. More details are provided in Supplementary Fig. 4–1, 4–2 and Supplementary Table 4–1 of Supplementary Note 4. The performance metrics of our work exhibit certain advantages over those of other reported infrared detectors and even commercial infrared detectors (see Supplementary Tables 5–1, 5–2 and 5–3 for a comparative analysis of metrics).

Demonstration of circular polarization information imaging
To comprehensively evaluate and assess the device’s performance, stability, and application potential, a single-pixel imaging test system was established46,47. Figure 5a shows the structure diagram of the imaging system. The 1550 nm linearly polarized light emitted by the laser is modulated into CPL using a QWP. The modulated light is then passed through a scanning mask with the pattern “SPMS” and projected onto the device. The mask is controlled to move linearly in the horizontal plane by an electrical displacement stage. The real-time photocurrent at the relevant photosensitive location is recorded using a source meter.

Notably, the gate voltage effectively modulates the interlayer carrier concentration and transport in the sandwich-structured device, thereby tuning the CPGE34,48. As shown in the gate-voltage dependence in Fig. 5b, applying a negative gate voltage significantly enhances the bipolar photocurrent response of the device to CPL. Furthermore, we investigated how different gate voltages regulate the variation of photocurrent with the QWP angle, as illustrated in Fig. 5c. The results indicate that the amplitude of the photocurrent, which follows a sinusoidal relationship with the QWP angle, can be stably enhanced by a negative gate voltage. The responsivity of the device is improved to be about 0.1 A/W with Vg = 2 V.

To study the imaging ability of the device under gate voltage modulation behavior, the imaging measurements under illumination of LCP and RCP were carried out with Vg = 0 V and Vg = −2 V, respectively, as shown in Fig. 5d. The application of gate voltage effectively enhances the clarity and contrast of the imaging pattern. Based on the previously mentioned broadband response capability, the imaging wavelength range should not be limited to this, but should also extend to the mid-infrared range for imaging. This ability to detect in the mid-infrared range can meet the practical detection needs of various application scenarios, thereby demonstrating significant application value. More imaging characterization can be found in Supplementary Fig. 5–1, 5–2 of Supplementary Note 5.

Methods
Device fabrication
The twist-stacked b-p devices were fabricated via a dry transfer method. The entire fabrication process was conducted within a glove box with water and oxygen levels maintained below 1 ppm. First, b-p flakes were mechanically exfoliated onto a Polydimethylsiloxane (PDMS) substrate and then transferred onto a silicon substrate. The thickness of the b-p flakes was determined by optical contrast. A stack was assembled by sequentially picking up three individual b-p layers using a Polycarbonate (PC)/PDMS stamp. Subsequently, the entire stack was transferred onto prepatterned bottom electrodes Cr/Au (2/30 nm) to establish electrical contact. A top BN was picked up using another PC/PDMS stack to cover the whole stack. Finally, a selected graphite flake was transferred onto the top hexagonal boron nitride (h-BN) layer to function as the top gate electrode.

To ensure high-precision layer stacking and reliable electrical contacts, we employed the following approach:
First, we developed a custom high-precision transfer system. The rotation motor integrated into our ‘Angwei’ transfer stage allows for accurate angular control, enabling twist angles with an uncertainty of only ±0.1°.
Second, we adopted a layer-by-layer van der Waals pick-up technique, as illustrated in. Using a glass slide/PDMS/polycarbonate stamp combination, we are able to pick up individual black phosphorus flakes, precisely control their orientation, and stack them gradually to minimize interfacial bubbles

Characterization methods
For the photocurrent scanning mapping setup, the 633, 1550 and 2700 nm lasers were directed by a single-mode fiber to the homemade setup. The light passes through a lens, a polarizer, and a quarter-wave plate. The laser beam was focused by an objective into a sub-micrometer diameter on the sample surface. Cisystems SR200N was used as the black-body radiation source, and the maximum temperature can reach 1200 K. For the electrical measurement setup, the longitudinal voltage and gate voltage were applied using a Keithley 2604B source meter. An FS Pro Integrated Semiconductor Parameter Testing System (Noise Analyzer) was used to measure the photocurrent, noise, and resistance of the device.

Simulation
We utilized the density functional theory (DFT) code, specifically the Vienna ab initio simulation package (VASP), to optimize the crystal structure and calculate the fundamental electronic properties. The self-consistent calculations were performed using a k-mesh of size 5×5×1 for the two considered twisted bilayer systems. The energy cutoff was set to be 500 eV, and the tolerance for the total energy was set to be less than 10^-5 eV. Exchange interactions and electron correlation were treated within the generalized gradient approximation proposed by Perdew, Burke, and Ernzerhof.

Data availability
All the technical details for producing the figures are provided in the supplementary information. The data are available from the corresponding authors X. C. (chenxl@sustech.edu.cn); X. L. Y. (yuxlong6@mail.sysu.edu.cn); C. W. Q. (chengwei.qiu@nus.edu.sg) and W. B. G. (wbgao@ntu.edu.sg) upon request.

Code availability
All the technical details for implementing the simulation are provided in the Supplementary Information. Codes are available from the corresponding authors upon request.

Peer review rounds
[{"round": 1, "reviewer_comments": {"reviewer_1": "The authors proposed a twist-stacked black phosphorus detector capable of broadband bipolar circular polarization detection. The theoretical analysis and experimental data are comprehensive, and compared with other circular polarization detectors, this work demonstrates multiple performance breakthroughs, making the approach a valuable reference. I suggest that certain aspects still require revision before publication.\n1. What are the main factors influencing the twist angle between the upper and lower layers? If the angle is changed, how would the effect differ? The authors could provide further discussion and supplementation through calculations and simulations.\n2. The circular polarization responses in Figure 3 differ greatly under different connection configurations, but the related descriptions of the corresponding physical processes are not sufficiently detailed and should be further supplemented.\n3. The RCD signal is shown in Figure 3b. The authors should describe the measurement methodology used to obtain it. How to evaluate the rationality of using this metric to determine the degree of chirality.\n4. From the RCD measurements in Figure 3b, it is evident that regions with strong chirality are observed. The bilayer-overlapped region also exhibits certain chirality; however, it remains unclear why the measured circular polarization response is significantly weaker than that of the trilayer-overlapped region device.\n5. Regarding Figure 4, why do intralayer contacts and interlayer contacts exhibit different I–V characteristics, and is this a necessary condition in this context?\n6. Although this work demonstrates significant advantages in performance, the twist-stacked structure introduces considerable complexity and challenges for device fabrication. How can this issue be addressed?\n7. Can similar results be obtained in other non-chiral materials, such as TMDs, in addition to black phosphorus?", "reviewer_2": "Jiang H. et al. proposed that the twisted stacked BP structures can generate strong chirality and enable chiral detection, which is quite interesting. This design is supported by both experimental and theoretical results. Besides, the detector shows advantages in infrared chiral detection. Overall, the work is of high quality and deserves to be published in NC. Here are some revision suggestions:\n1. As shown in Fig. 3 and Supplementary Fig. 3-2, despite the structural design, the device exhibits responses to both circularly and linearly polarized light. The authors are encouraged to clarify how this trade-off is addressed, and whether the response to linearly polarized light is intended to be preserved or suppressed.\n2. The authors should clarify how the twist angle affects the CPGE response and whether the angle presented represents a unique solution.\n3. The work in Sci. Adv. 8, eabo0375 (2022) also reported that a BP detector exhibits a response to circularly polarized light. However, the mechanisms in these two cases appear to be entirely different. A detailed discussion is therefore necessary.\n4. If other two-dimensional materials, for instance, isotropic ones, were employed in this system, could the interference from the linear polarization response be more effectively suppressed? The authors are encouraged to discuss possible avenues for improving the present device.\n5. In the RCD measurements of Fig. 3, strong chirality is observed in both the bilayer and trilayer overlapping regions. The authors are encouraged to evaluate how these differences manifest in the detector performance.\n6. How is the RCD measurement performed, and does it require an applied magnetic field? If not, the labeling in Supplementary Fig. 2-3 should be corrected.", "reviewer_3": "This work reports a device for detecting circularly polarized light. Using twist-stacked black phosphorus as the sensitive material, the authors were able to detect circularly polarized light and detect a shift in the photocurrent polarity. However, the work’s innovation and the device's performance are substandard. Therefore, I recommend rejection. The reasons are as follows.\na. This work is not innovative enough. Many papers have already reported on the use of angled design in two-dimensional materials to detect polarized light. Furthermore, the authors are aware that controlling the twisting and stacking of multilayer two-dimensional materials at specific angles has become a common strategy for introducing optical chirality into achiral systems.\nb. The authors claim that this work satisfies multispectral detection requirements in complex scenarios, but the results show that it only achieves a wide spectral response and lacks multispectral detection capabilities. This is confusing.\nc. Judging from the optical photos of the device, the author’s control over the interface is very rough, and it is difficult to ensure that these uncontrollable factors will have a negative impact on the device performance noise.\nd. The device’s response to blackbody radiation is also unsatisfactory. The blackbody responsivity is an order of magnitude lower than the laser responsivity. What accounts for this discrepancy? The test setup lacks a filter. Therefore, when exposed to a blackbody temperature exceeding 750K, the wavelength of light emitted is primarily within the visible spectrum. Furthermore, the device’s photocurrent switching characteristics indicate insensitivity to blackbody radiation."}, "author_response": "Reply to the reviewers:\nReviewer 1\nComments:\nThe authors proposed a twist-stacked black phosphorus detector capable of broadband bipolar\ncircular polarization detection. The theoretical analysis and experimental data are comprehensive,\nand compared with other circular polarization detectors, this work demonstrates multiple\nperformance breakthroughs, making the approach a valuable reference. I suggest that certain\naspects still require revision before publication.\nAuthor Reply: We are grateful to the reviewers for your questions and suggestions, which will\ngreatly enhance the quality of our manuscript. The following are our point-by-point responses to\nthe questions you raised, along with the corresponding revisions and additions. We hope these\naddress your concerns.\nComment 1. What are the main factors influencing the twist angle between the upper and lower\nlayers? If the angle is changed, how would the effect differ? The authors could provide further\ndiscussion and supplementation through calculations and simulations.\nAuthor Reply 1: We appreciate the reviewer pointing out the issue. In this work, we introduce a\ntwist angle to break the symmetry at the material interface and thereby induce chiral properties. In\nthe theoretical construction of the twisted system, the primary factor affecting the twist angle is\nthe lattice constant (under the condition of unchanged lattice symmetry). For instance, directional\nstretching or compression leading to different lattice constants will result in bilayer systems with\nvarying twist angles for the same supercell size ratio. Here, we employed the lattice parameters\nand the bilayer twist system construction method provided in PRB 96, 041411 (2017). Specifically,\na supercell needs to be constructed to realize the periodic structures of the upper and lower layers,\nand the lattice constants of the two supercells must be identical. We assume that one lattice vector\nof the top-layer supercell is b A pa /qa , where p and q are integers.\n1 1 2\nMb XafheX g[Tg g[X gjb _Tgg\\VX iXVgbef bY g[X fhcXeVX__ TeX beg[bZbaT_( Uâ VTa UX bUgT\\aXW Ul\nebgTg\\aZUáUl5,p(\\*X*(\na a\nÈ Ø\nb AMR A b A1Mq 2 a /Mp 1 a\nÉ Ù\n2 Ê 2 Ú 1 a 1 a 2\n1 2\nHere, M is a scaling factor, which can be determined from the condition that the supercell area\nmust be an integer multiple of the area of the primitive cell. For clarity, we directly provide the\nfinal result as follows:\na\nM A 2\na\nÎ b A pa /qa\n1 1 2\nÑ\na a\nÑb A1Mq 2 a /Mp 1 a\nÑ 2 a 1 a 2\nÑ\n1 2\nÏ\nb' A1pa /qa\nÑ 1 1 2\nÑ a a\nÑb' A1Mq 2 a 1Mp 1 a\n2 a 1 a 2\nÑÐ\n1 2\nIn these expressions, the first two lattice vectors correspond to the top-layer system, while the\nlatter two correspond to the bottom-layer system. They satisfy the relation b A b' (b A b'\n1 1 2 2\nand, within each layer, the two lattice vectors are mutually orthogonal. Next, we calculate the twist\nTaZ_XƒUXgjXXag[XgbcTaWUbggb`_TlXefTfYb__bjf6\nb ¹b' p2 /q2 cos2 / q2 1 p2\ncos A 1 1 A\nb ¹ b' p2 /q2 / q2 1 p2 cos2\n1 1\na\nWhere tan A 1 , andthe area ratio between the supercell and the primitive cell is given by:\na\n2\nb b M p2 a 2 /q2 a 2 È a a Ø a 2\n1 2\nA 1 2 A A M É p2 1 /q2 2 ÙA p2 /q2 2\na a a a É a a Ù a 2\n1 2 1 2 Ê 2 1 Ú 1\nTherefore, different choices of p and q lead to different twist angles between the two layers,\nas well as supercells of varying sizes. From this, we obtain several possible twist angles and their\ncorresponding supercell sizes for the lattice constants considered in the manuscript, as shown in\nTable R1.\nTable R1*Mj\\fgTaZ_XƒTaWVbeeXfcbaW\\aZf\\mXeTg\\bUXgjXXafhcXeVX__TaWha\\gVX__„.\nWe conducted detailed calculations on two additional twisted systems with angles of\nƒ=70.5°and 31.6°, analyzing their electronic structures and electron state distributions, as\nillustrated in the Figure R1.1 a and b. It can be observed that these systems exhibit results similar\nto those of the twisted system considered in the manuscript. Specifically, both systems retain\ninsulating characteristics, with the valence band maximum (VBM) and conduction band minimum\n&<;F' _bVTgXW Tg g[X (cid:129) cb\\ag* <b`cTe\\aZ g[X X_Xctron state distributions at the VBM and CBM,\nthe latter shows more electron states distributed within the interlayer gaps, providing a transport\nchannel along the z-direction. This enables carriers excited to the CBM to achieve z-directional\ntransport. The symmetry breaking induced by interlayer twisting, along with the experimentally\nvaried layer thicknesses (corresponding to different work functions), ultimately facilitates\neffective unidirectional current transmission.\nTherefore, the two selected twist angles can also reproduce the experimental phenomena\npresented in the manuscript. However, considering the influence of the linearly polarized\ncomponent, the angles chosen in this work exhibit relatively superior performance.\nFigure R1.1. The band structures and the side views of the spatial distribution of electron states at\nthe conduction band minimum and valence band maximum with twist angles n ~ 70° (a) and\n1\ntwist angles n ~ 31° (b),respectively.\nAuthor action 1: We have incorporated the above theoretical derivations into Supplementary\nNote 1 and highlighted them in red.\nComment 2. The circular polarization responses in Figure 3 differ greatly under different\nconnection configurations, but the related descriptions of the corresponding physical processes\nare not sufficiently detailed and should be further supplemented.\nAuthor Reply 2: PX TcceXV\\TgX g[X eXi\\XjXeyf \\af\\Z[gYh_ dhXfg\\ba* AXeX( jX cebi\\WX T WXgT\\_XW\ndescription of the physical processes responsible for the observed photoresponse when different\nlayers are connected. As illustrated in Figure R1.1, the collected photocurrent mainly originates\nfrom two distinct contributions. The first is the circular photocurrent generated at the twist\ninterface, which is sensitive only to circularly polarized light (RCP/LCP). The second arises from\nthe intrinsic response of each individual BP layer, which is sensitive only to linearly polarized\nlight (LP).\nSince circularly polarized light can be regarded as a superposition of two orthogonal linear\npolarizations, illumination of the system by circularly polarized light inevitably induces\nphotocurrent components associated with both circular and linear polarizations. Our design and\nelectrode connections are thus aimed at enhancing the photocurrent induced by RCP/LCP while\nsuppressing that induced by LP, thereby maximizing the circularly polarized component of the\noverall response.\n1. When the top and middle BP layers are connected (as shown in the first row of Figure\nR1.1):\n(1) Under circularly polarized excitation, due to the circular photogalvanic effect (CPGE),\nRCP generates an upward-directed photocurrent, whereas LCP produces a downward-\ndirected photocurrent with the opposite polarity.\n(2) Under linearly polarized excitation, when the polarization direction is aligned with the\narmchair crystal orientation of the top (LP1), middle (LP2), or bottom (LP3) BP layers,\nphotocurrents of varying magnitudes flow upward.\n2. When the middle and bottom BP layers are connected (as shown in the second row of\nFigure R1.2):\n(1) Under CPGE, RCP again induces an upward photocurrent, while LCP leads to a\ndownward photocurrent.\n(2) Under LP illumination, when the polarization direction is aligned with the armchair\ncrystal orientation of the three BP layers (LP1, LP2, LP3), photocurrents of different\nmagnitudes flow downward.\n3. When the top and bottom BP layers are connected, the response can be viewed as a\nsuperposition of the above two cases. In this configuration, the circular photocurrents\ninduced by RCP and LCP add constructively, while the linearly polarized photocurrents\npartially cancel each other. Consequently, the influence of LP is minimized when the top\nand bottom BP layers are connected.\nThis explains why in Figures 3d and 3e, the connection between the top and bottom BP layers\nenables bipolar detection of circularly polarized light, effectively highlighting the dominance of\nthe circular photogalvanic response.\nFigure R1.2 Analysis of photocurrent components\nAuthor action 2: We have added the above analysis to Supplementary Note 2 and highlighted it in\nred.\nComment 3. The RCD signal is shown in Figure 3b. The authors should describe the\nmeasurement methodology used to obtain it. How to evaluate the rationality of using this\nmetric to determine the degree of chirality.\nAuthor Reply 3: We appreciate the reviewer pointing out the issue. All optical measurements\nwere performed in a home-built confocal optical microscope. Seen in Figure R1.3, we use\nReflective circular dichroism (RCD) spectroscopy experimental setup to obtain the RCD signal.\n:Ž€Ž1, bU]XVg\\iX &ah`Xe\\VT_ TcXegheX( ,*2/' j\\g[ T fcbg f\\mX bY -Žµm was used to collect RCD\nsignal. The reflective circular dichroism (RCD) measurement was performed with a continuous\nwave laser (HUBNER Photonics C-WAVE VIS), which produced a narrow MHz bandwidth laser,\nranging -,4,Ža` gb -30,Ža`* M[X XkV\\gTg\\ba _TfXe jTf Y\\efg cTffXW g[ebhZ[ Ta bcg\\VT_ V[bccXe Tg\nYeXdhXaVl Y- 5-.ŽAm TaW g[Xa cb_Te\\mXW 01p gb g[X c[bgbX_Tfg\\V `bWh_Tgbe &I>F-100) fast axis\nwith a maximum retaeWTaVX bY +0* M[X WXcTeg\\aZ V\\eVh_Te_l cb_Te\\mXW _\\Z[g bfV\\__TgXf UXgjXXa\nright circular polarized light and left circular polarized light in a sinusoidal time-dependence with\nT YeXdhXaVl Y. 1,*1Ž^Am* M[X eXY_XVgXW f\\ZaT_ Yeb` g[X fT`c_X \\f eXY_XVgXW Ul T beamsplitter and\nsent into an InGaAs avalanche photodiode (Thorlabs APD430C/M). The photodiode current was\namplified and turned into voltage signal by SR570 and sent into two lock-in amplifiers set at\n1,*1Ž^AmTaW5-.ŽAm( Z\\i\\aZ g[X K<= f\\ZaT_ (voltage signal V1) and the laser excitation intensity\n(voltage signal V2), respectively. The final CD signal is given by RCD = V1/V2.\nFigure R1.3Set up of RCD\nEarly instruments used mechanical devices (like rotating quarter-wave plates) to alternate\nbetween LCP and RCP. This method is slow and susceptible to vibration and misalignment. The\nprimary advantage of using a PEM for measuring RCD is its ability to achieve extremely high\nsensitivity and signal-ttoo-noise ratio (SNR)by enabling precise, high-frequency phase modulation.\nRCD signal reflects differential absorption of left and right circularly polarized (LCP and\nRCP) light, induced in a sample. It is an effective method to determine the degree of chirality.\nAuthor action3:We have added the above descriptions and figures to Supplementary Figs. 2t44..\nComment 4. From the RCD measurements in Figure 3b, it is evident that regions with strong\nchirality are observed. The bilayer-overlapped region also exhibits certain chirality; however, it\nremains unclear why the measured circular polarization response is significantly weaker than that\nof the trilayer-overlapped region device.\nAuthor Reply 4: We sincerely thank the reviewer for raising this important question. Indeed, as\nshown in the RCD mapping, all twisted black phosphorus regions exhibit strong chirality, with the\ntrilayer-overlapped region showing the strongest response. However, the circularly polarized\nphotodetection performance obtained by connecting the top and bottom layers is significantly\nbetter than that of adjacent-layer connections, which is closely related to the analysis in the\nComment 2.\nAs discussed above, the prominence of the circularly polarized response mainly depends on\nthe ratio of the circularly polarized component to the total photocurrent response. When only two\nlayers are connected, the response is more strongly affected by the linearly polarized component,\nwhereas the trilayer configuration can effectively compensate part of the linear polarization\ncontribution, thereby optimizing the circular polarization detection.\nComment 5. Regarding Figure 4, why do intralayer contacts and interlayer contacts exhibit\ndifferent IhV characteristics, and is this a necessary condition in this context?\nAuthor Reply 5: We sincerely thank the reviewer for this insightful question. The distinct ItV\ncharacteristics observed between intralayer and interlayer contacts originate from the trilayer\nblack phosphorus (BP) architecture. In addition to enhancing the chiral response induced by\ntwisted BP, an important motivation for designing the trilayer structure is to exploit vertical\nelectrostatic symmetry to suppress the linear polarization (LP) response from individual BP layers.\nAs illustrated in Figure R1.4, the device consists of relatively thinner top and bottom BP\nlayers and a thicker middle BP layer. Owing to the difference in work function between the thicker\n(middle) and thinner (top and bottom) BP layers, vertically symmetric homojunctions are formed,\nresulting in a symmetric potential distribution along the vertical direction. Since the transport of\nphotogenerated carriers induced by linearly polarized light in the top and bottom layers depends\non the interlayer potential, this symmetric potential design helps to mitigate the LP component of\nthe photocurrent during detection.\nIt can thus be inferred that the ItV characteristics between different layers are determined by\nthe work function difference between the thick and thin BP layers in this configuration. This\nbehavior differs from that of intralayer ItV characteristics and is, in fact, essential for achieving\nthe desired device functionality.\nFigure R1.4 Trilayer black phosphorus architecture and vertical potential distribution\nComment 6. Although this work demonstrates significant advantages in performance, the twist-\nstacked structure introduces considerable complexity and challenges for device fabrication. How\ncan this issue be addressed?\nAuthor Reply 6: We sincerely thank the reviewer for raising this important point. The challenge\nof achieving precise alignment and bubble-free interfaces in the fabrication of stacked 2D\nmaterials is indeed a significant hurdle, which we have addressed through a carefully developed\ntransfer and contact methodology. To ensure high-precision layer stacking and reliable electrical\ncontacts, we employed the following approach:\nFirst, we developed a custom high-precision transfer system. The rotation motor integrated\n\\agb bhe x:aZjX\\y geTafYXe fgTZX T__bjf Ybe TVVheTgX TaZh_Te Vbageb_( XaTU_\\aZ gj\\fg TaZ_Xf j\\g[ Ta\nuncertainty of only ±0.1°.\nSecond, we adopted a layer-bbyy-layer van der Waals pick-up technique, as illustrated in Reply\nFigure R11..5. Using a glass slide/PDMS/polycarbonate stamp combination, we are able to pick up\nindividual black phosphorus (BP) flakes, precisely control their orientation, and stack them\ngradually to minimize interfacial bubbles (Figure R1.5b).\nFor the electrical contacts, we pre-patterned bottom electrodes (Cr/Au: 2/30 nm) onto the\nsubstrate prior to transfer (Figure R1.5a). The BP layers were then transferred directly onto these\nelectrodes. To ensure ohmic contact quality, an additional layer of graphite was applied over the\ncontact area, serving simultaneously as both a top gate and a contact gate, as shown in Figure\nR1.4d.\nFigure R1.5Twist trilayer black phosphorusFabrication process\nAuthor action6: We have added the relevant descriptions to the Methods section of the\nmain text and marked them in red.\nComment 7. Can similar results be obtained in other non-chiral materials, such as TMDs, in\naddition to black phosphorus?\nAuthor Reply 7: We sincerely thank the reviewer for this forward-looking question. This is\nindeed an ongoing direction of our researchuexploring chiral detection using more stable,\nnonchiral material systems such as TMDs. The breaking of symmetry can be achieved through\ntwist and vertical stacking. We are currently experimenting with multilayer TMDs having different\ntwist angles, while simultaneously employing machine learning to learn and analyze the Stokes\nparameters for efficient circular polarization detection.\nAuthor action 7:We have added the above discussion to the Discussion section of the main text.\nReviewer 2\nComments: Jiang H. et al. proposed that the twisted stacked BP structures can generate strong\nchirality and enable chiral detection, which is quite interesting. This design is supported by both\nexperimental and theoretical results. Besides, the detector shows advantages in infrared chiral\ndetection. Overall, the work is of high quality and deserves to be published in NC. Here are some\nrevision suggestions:\nAuthor Reply: We appreciate the reviewers' affirmations and constructive feedback. Your\nvaluable suggestions and comments have helped us better highlight and clarify the underlying\nphysical processes and the uniqueness of our work, thereby improving the overall quality of the\nmanuscript. Below, we provide our point-by-point responses along with extensive revisions and\nadditions, which we hope will satisfactorily address your concerns.\nComments 1: As shown in Fig. 3 and Supplementary Fig. 3-2, despite the structural design, the\ndevice exhibits responses to both circularly and linearly polarized light. The authors are\nencouraged to clarify how this trade-off is addressed, and whether the response to linearly\npolarized light is intended to be preserved or suppressed.\nAuthor Reply 1: We sincerely thank the reviewer for raising this important and balancing\nquestion. The core motivation of our design is indeed to regulate the relative contributions of the\nlinear and circular polarization response components. While the linear polarization component can\nbe partially suppressed, it cannot be completely eliminated. Below, we provide a detailed analysis\nfrom the perspective of the individual photocurrent components.\nAs illustrated in Figure R2.1, the collected photocurrent mainly originates from two distinct\ncontributions. The first is the circular photocurrent generated at the twist interface, which is\nsensitive only to circularly polarized light (RCP/LCP). The second arises from the intrinsic\nresponse of each individual BP layer, which is sensitive only to linearly polarized light (LP).\nSince circularly polarized light can be regarded as a superposition of two orthogonal linear\npolarizations, illumination of the system by circularly polarized light inevitably induces\nphotocurrent components associated with both circular and linear polarizations. Our design and\nelectrode connections are thus aimed at enhancing the photocurrent induced by RCP/LCP while\nsuppressing that induced by LP, thereby maximizing the circularly polarized component of the\noverall response.\n1. When the top and middle BP layers are connected (as shown in the first row of Figure\nR1.1):\n(1) Under circularly polarized excitation, due to the circular photogalvanic effect (CPGE), RCP\ngenerates an upward-directed photocurrent, whereas LCP produces a downward-directed\nphotocurrent with the opposite polarity.\n(2) Under linearly polarized excitation, when the polarization direction is aligned with the\narmchair crystal orientation of the top (LP1), middle (LP2), or bottom (LP3) BP layers,\nphotocurrents of varying magnitudes flow upward.\n2. When the middle and bottom BP layers are connected (as shown in the second row of\nFigure R2.1):\n(1) Under CPGE, RCP again induces an upward photocurrent, while LCP leads to a downward\nphotocurrent.\n(2) Under LP illumination, when the polarization direction is aligned with the armchair\ncrystal orientation of the three BP layers (LP1, LP2, LP3), photocurrents of different magnitudes\nflow downward.\n3. When the top and bottom BP layers are connected, the response can be viewed as a\nsuperposition of the above two cases. In this configuration, the circular photocurrents induced by\nRCP and LCP add constructively, while the linearly polarized photocurrents partially cancel each\nother. Consequently, the influence of LP is minimized when the top and bottom BP layers are\nconnected.\nFigure R2.1 Analysis of photocurrent components\nTherefore, although the linear polarization response cannot be completely eliminated, it does\nnot compromise the high-performance circular polarization detection of the device. Conversely,\nthis feature can be advantageously utilized in scenarios requiring linear polarization detection,\nwhere the same device can also operate effectively. As shown by the series of results in Figure\nR2.2 for linear polarization response measurements, by altering the electrode connection\nconfiguration, the device can achieve broadband and high polarization-ratio linear polarization\ndetection, although its responsivity is somewhat lower compared to circular polarization detection.\nFigure R2.2. Linear polarization detection performance of the device. a, A schematic diagram\nof the twisted-stacking b-p. The top, middle, and bottom b-p are labeled as layer A, B, and C,\nrespectively. b, Photoswitching response of A-B mode and C-B mode when polarization angle is\nrotated from 0° to 180° with a step of 20° at V Ž9Ž,ŽO TaW haWXe 1.55Ž†` _TfXe \\__h`\\aTg\\ba j\\g[\nDS\nan incident intensity of 50Ž+W. c, Photocurrents of A-C mode as a function of polarization angles\nat different incident intensities (10, 20, 30, 40 and 50 +W) under 1.55Ž†`_TfXe\\__h`\\aTg\\ba*M[XfX\nphotocurrents were measured at V Ž9Ž,ŽO*d, Two-dimensional plots of photocurrents measured\nDS\nfrom the A-B layer and C-B layer, enabling unambiguous determination of polarization angle\nfrom 0° to 180° and incident intensity from 50 +W to 150 +W.\nAuthor action 1: We have added the above analysis to Supplementary Note 2 and highlighted it in\nred.\nComment 2: The authors should clarify how the twist angle affects the CPGE response and\nwhether the angle presented represents a unique solution.\nAuthor Reply 2: In this work, we introduce a twist angle to break the symmetry at the material\ninterface and thereby induce chiral properties. It is worth noting that the twist angles discussed\nhere are not unique solutions, a fact that we verify through theoretical calculations.\nIn the theoretical construction of the twisted system, the primary factor affecting the twist\nangle is the lattice constant (under the condition of unchanged lattice symmetry). For instance,\ndirectional stretching or compression leading to different lattice constants will result in bilayer\nsystems with varying twist angles for the same supercell size ratio. Here, we employed the lattice\nparameters and the bilayer twist system construction method provided in PRB 96, 041411 (2017).\nSpecifically, a supercell needs to be constructed to realize the periodic structures of the upper and\nlower layers, and the lattice constants of the two supercells must be identical. We assume that one\nlattice vector of the top-layer supercell is b A pa /qa , where p and q are integers.\n1 1 2\nMb XafheX g[Tg g[X gjb _Tgg\\VX iXVgbef bY g[X fhcXeVX__ TeX beg[bZbaT_( Uâ VTa UX bUgT\\aXW Ul\nebgTg\\aZUáUl5,p(\\*X*(\na a\nÈ Ø\nb AMR A b A1Mq 2 a /Mp 1 a\nÉ Ù\n2 Ê 2 Ú 1 a 1 a 2\n1 2\nHere, M is a scaling factor, which can be determined from the condition that the supercell area\nmust be an integer multiple of the area of the primitive cell. For clarity, we directly provide the\nfinal result as follows:\na\nM A 2\na\nÎ b A pa /qa\n1 1 2\nÑ\na a\nÑb A1Mq 2 a /Mp 1 a\nÑ 2 a 1 a 2\nÑ\n1 2\nÏ\nb' A1pa /qa\nÑ 1 1 2\nÑ a a\nÑb' A1Mq 2 a 1Mp 1 a\n2 a 1 a 2\nÑÐ\n1 2\nIn these expressions, the first two lattice vectors correspond to the top-layer system, while the\nlatter two correspond to the bottom-layer system. They satisfy the relation b A b' (b A b'\n1 1 2 2\nand, within each layer, the two lattice vectors are mutually orthogonal. Next, we calculate the twist\nTaZ_XƒUXgjXXag[XgbcTaWUbggb`_TlXefTfYb__bjf6\nb ¹b' p2 /q2 cos2 / q2 1 p2\ncos A 1 1 A\nb ¹ b' p2 /q2 / q2 1 p2 cos2\n1 1\na\nWhere tan A 1 , andthe area ratio between the supercell and the primitive cell is given by:\na\n2\nb b M p2 a 2 /q2 a 2 È a a Ø a 2\n1 2\nA 1 2 A A M É p2 1 /q2 2 ÙA p2 /q2 2\na a a a É a a Ù a 2\n1 2 1 2 Ê 2 1 Ú 1\nTherefore, different choices of p and q lead to different twist angles between the two layers,\nas well as supercells of varying sizes. From this, we obtain several possible twist angles and their\ncorresponding supercell sizes for the lattice constants considered in the manuscript, as shown in\nTable R2.\nTable R2*Mj\\fgTaZ_XƒTaWVbeeXfcbaW\\aZf\\mXeTg\\bUXgjXXafhcXeVX__TaWha\\gVX__„.\nWe conducted detailed calculations on two additional twisted systems with angles of\nƒ=70.5°and 31.6°, analyzing their electronic structures and electron state distributions, as\nillustrated in the Figure R2.3 a and b. It can be observed that these systems exhibit results similar\nto those of the twisted system considered in the manuscript. Specifically, both systems retain\ninsulating characteristics, with the valence band maximum (VBM) and conduction band minimum\n&<;F' _bVTgXW Tg g[X (cid:129) cb\\ag* <b`cTe\\aZ g[X X_XVgeba fgTgX W\\fge\\Uhg\\baf Tg g[X O;F TaW <;F(\nthe latter shows more electron states distributed within the interlayer gaps, providing a transport\nchannel along the z-direction. This enables carriers excited to the CBM to achieve z-directional\ntransport. The symmetry breaking induced by interlayer twisting, along with the experimentally\nvaried layer thicknesses (corresponding to different work functions), ultimately facilitates\neffective unidirectional current transmission.\nTherefore, the two selected twist angles can also reproduce the experimental phenomena\npresented in the manuscript. However, considering the influence of the linearly polarized\ncomponent, the angles chosen in this work exhibit relatively superior performance.\nFigure R2.3. The band structures and the side views of the spatial distribution of electron states at\nthe conduction band minimum and valence band maximum with twist angles n ~ 70° (a) and\n1\ntwist angles n ~ 31° (b),respectively.\nAuthor action 2: We have incorporated the above theoretical derivations into Supplementary\nNote 1 and highlighted them in red.\nComment 3. The work in Sci. Adv. 8, eabo0375 (2022) also reported that a BP detector exhibits a\nresponse to circularly polarized light. However, the mechanisms in these two cases appear to be\nentirely different. A detailed discussion is therefore necessary.\nAuthor Reply 3: We sincerely thank the reviewer for raising this important point, as without\nclarification it could indeed lead to the misconception that our work is similar to the referenced\nstudy. The work mentioned by the reviewer provides an excellent demonstration of using twisted\nBP for the design of a polarization analyzer at an optical fiber end facet. However, our work\ndiffers fundamentally in terms of device architecture, operating mechanism, and the circular\npolarization detection performance.\n1. Device architecture\nThe designed fiber-integrated polarimeter in Sci. Adv. 8, eabo0375 (2022) consists of\nthree sequentially stacked units on a flat optical fiber end face, as schematically shown\nin Figure R2.4a. Each unit includes a pair of asymmetrical electrodes, a layer of light-\nharvesting materials and a layer of hexagonal boron nitride (hBN) flakes for insulation and\nencapsulation. The Bi Se layer at the bottom is to calibrate incident light power and two\n2 3\ntwistedly stacked anisotropic BP layers for precise polarization sensing.\nTherefore, in the referenced work, each BP layer is encapsulated and separated by BN,\nfunctioning as an independent unit for linear polarization detection without mutual\ninterference. In contrast, our trilayer BP structure features direct twist-contact between layers,\nforming two interfacial contacts, as shown in Figure R2.4b. These contact interfaces are the\nkey sites for generating the circular photogalvanic effect (CPGE), highlighting a fundamental\nstructural difference between the two approaches.\n[REDACTED]\nFigure R2.4. a, Device architecture in Sci. Adv. 8, eabo0375 (2022). b, Device architecture in this\nwork.\n2. Operating mechanism\nAs mentioned above, since the referenced work in Sci. Adv. 8, eabo0375 (2022) consists\nof independent BP layers, the BP itself is not intrinsically sensitive to circularly polarized light.\nThe photocurrent generation in that case arises from a self-driven effect. Figure R2.5a shows\nthat the asymmetrical design of electrodes against the fiber core will result in a nonuniform\nillumination to the BP unit and generate spontaneous photocurrents. Thus, the photocurrent\nresponse to circularly polarized light in that work is attributed to the asymmetric electrode\ndesign rather than the material itself.\nIn our work, the photocurrent response to circularly polarized light originates from the\nCPGE generated at the twisted interfaces. As illustrated in the Figure R2.5b, the direction of\nthe circular photocurrent depends on the handedness of the chirality, which represents a\nfundamental difference from the aforementioned approach.\n[REDACTED]\nFigure R2.5. a, Operating mechanism in Sci. Adv. 8, eabo0375 (2022). b, Device architecture in\nthis work.\n3. Circular polarization detection performance\nDue to the differences in device structure and operating mechanism, the resulting circular\npolarization detection performance also differs significantly. In the referenced work in Sci. Adv. 8,\neabo0375 (2022), the photocurrent signal requires rotating a QWP and performing calculations to\nextract the circular polarization information (Figure R2.6a). In contrast, our device enables direct\nbipolar detection of LCP and RCP, as shown in Figure R2.6b.\n[REDACTED]\nFigure R2.6. a, Circular polarization detection performance in Sci. Adv. 8, eabo0375 (2022). b,\nDevice architecture in this work.\nIn summary, the two works are fundamentally different and serve distinct purposes. The\nreferenced study focuses on polarization calibration and sensing for optical fibers, whereas our\nwork is well-suited for high-performance circular polarization detection and imaging.\nComment 4. If other two-dimensional materials, for instance, isotropic ones, were employed in\nthis system, could the interference from the linear polarization response be more effectively\nsuppressed? The authors are encouraged to discuss possible avenues for improving the present\ndevice.\nAuthor Reply 4: We sincerely thank the reviewer for this forward-looking question. This is\nindeed an ongoing direction of our researchuexploring chiral detection using more stable,\nnonchiral material systems such as TMDs. The breaking of symmetry can be achieved through\ntwist and vertical stacking. We are currently experimenting with multilayer TMDs having different\ntwist angles, while simultaneously employing machine learning to learn and analyze the Stokes\nparameters for efficient circular polarization detection.\nAuthor action 4: We have added the above discussion to the Discussion section of the main text.\nComment 5. In the RCD measurements of Fig. 3, strong chirality is observed in both the bilayer\nand trilayer overlapping regions. The authors are encouraged to evaluate how these differences\nmanifest in the detector performance.\nAuthor Reply 5: We sincerely thank the reviewer for raising this important question. Indeed, as\nshown in the RCD mapping, all twisted black phosphorus regions exhibit strong chirality, with the\ntrilayer-overlapped region showing the strongest response. However, the circularly polarized\nphotodetection performance obtained by connecting the top and bottom layers is significantly\nbetter than that of adjacent-layer connections, which is closely related to the analysis in the\nComment 1.\nAs discussed above, the prominence of the circularly polarized response mainly depends on\nthe ratio of the circularly polarized component to the total photocurrent response. When only two\nlayers are connected, the response is more strongly affected by the linearly polarized component,\nwhereas the trilayer configuration can effectively compensate part of the linear polarization\ncontribution, thereby optimizing the circular polarization detection.\nComment 6. How is the RCD measurement performed, and does it require an applied magnetic\nfield? If not, the labeling in Supplementary Fig. 2-3 should be corrected.\nAuthor Reply 6: We appreciate the reviewer pointing out the issue. No magnetic field was\napplied during this measurement. The specific procedure is as follows. All optical measurements\nwere performed in a home-built confocal optical microscope. Seen in Figure R2.7, we use\nReflective circular dichroism (RCD) spectroscopy experimental setup to obtain the RCD signal.\n:Ž€Ž1, bU]XVg\\iX &ah`Xe\\VT_ TcXegheX( ,*2/' j\\g[ T fcbg f\\mX bY -Žh` jTf hfXW gb Vb__XVg K<=\nsignal. The reflective circular dichroism (RCD) measurement was performed with a continuous\nwave laser (HUBNER Photonics C-WAVE VIS), which produced a narrow MHz bandwidth laser,\nranging -,4,Ža` gb -30,Ža`* M[X XkV\\gTg\\ba _Tser was first passed through an optical chopper at\nYeXdhXaVl Y- 5-.ŽAm TaW g[Xa cb_Te\\mXW 01p gb g[X c[bgbX_Tfg\\V `bWh_Tgbe &I>F-100) fast axis\nj\\g[ T `Tk\\`h` eXgTeWTaVX bY +0* M[X WXcTeg\\aZ V\\eVh_Te_l cb_Te\\mXW _\\Z[g bfV\\__TgXf UXgjXXa\nright circular polarized light and left circular polarized light in a sinusoidal time-dependence with\nT YeXdhXaVl Y. 1,*1Ž^Am* M[X eXY_XVgXW f\\ZaT_ Yeb` g[X fT`c_X \\f eXY_XVgXW Ul T UXT`fc_\\ggXe TaW\nsent into an InGaAs avalanche photodiode (Thorlabs APD430C/M). The photodiode current was\namplified and turned into voltage signal by SR570 and sent into two lock-in amplifiers set at\n1,*1Ž^Am TaW 5-.ŽAm( Z\\i\\aZ g[X K<= f\\ZaT_ (voltage signal V1) and the laser excitation intensity\n(voltage signal V2), respectively.The final CD signal is given by RCD = V1/V2.\nFigure R2.7Set up of RCD\nEarly instruments used mechanical devices (like rotating quarter-wave plates) to alternate\nbetween LCP and RCP. This method is slow and susceptible to vibration and misalignment. The\nprimary advantage of using a PEM for measuring RCD is its ability to achieve extremely high\nsensitivity and signal-ttoo-noise ratio (SNR)by enabling precise, high-frequency phase modulation.\nRCD signal reflects differential absorption of left and right circularly polarized (LCP and\nRCP) light, induced in a sample. It is an effective method to determine the degree of chirality.\nAuthor action6:We have added the above descriptions and figures to Supplementary Figs. 2t44..\nReviewer 3\nComments:\nThis work reports a device for detecting circularly polarized light. Using twist-stacked black\nphosphorus as the sensitive material, the authors were able to detect circularly polarized light and\ndetect a shift in the photocurrent polarity. However, the wo_Xi` V[[\\cNaV\\[ N[Q aUR QRcVPR%`\nperformance are substandard. Therefore, I recommend rejection. The reasons are as follows.\nAuthor Reply: We would first like to thank you for carefully reading our manuscript and for your\nprofessional and insightful questions. Your concerns mainly focus on the aspects of originality and\nperformance, which indeed highlight some weaknesses in the current version of our manuscript\nand provide valuable guidance for our revision. In response:\n1. We have conducted a comprehensive and in-depth review and comparison of the literature\nto demonstrate that existing material systems face significant challenges in achieving\neffective circular polarization detection solely through photocurrent mechanismsu\nchallenges that our approach successfully addresses. The novelty of our work lies in two\nkey firsts. First, we demonstrate for the first time the use of high-performance BP for\ncircularly polarized light detection. Second, we achieve bipolar and high-discrimination\nCPL detection through a twist-engineered sandwich stacking design. These advances\naddress the long-standing material bottlenecks and discrimination challenges in CPL\ndetection. We have additionally included Tables R3, R4, and R5 as supporting evidence\nfor the discussions.\n2. We have supplemented the manuscript with broader wavelength-range measurements to\nfurther demonstrate the advantages of our design in terms of operating bandwidth,\nresponsivity, and polarization ratio.\nWe hope that these extensive additions and supporting evidence adequately address your concerns.\nThe detailed point-by-point responses are provided below.\nComment 1.This work is not innovative enough. Many papers have already reported on the use of\nangled design in two-dimensional materials to detect polarized light. Furthermore, the authors are\naware that controlling the twisting and stacking of multilayer two-dimensional materials at\nspecific angles has become a common strategy for introducing optical chirality into achiral\nsystems.\nAuthor Reply 1: We thank the reviewer for raising questions regarding the originality of our work,\nwhich will help us better refine and highlight the innovations. Ba eXfcbafX gb g[X eXi\\XjXeyf\ncomments regarding the novelty of our work, we have conducted a thorough literature survey on\nall studies related to circularly polarized light detection based on twist-engineered 2D materials, to\nensure that no relevant work has been overlooked.\nAccording to our survey, controlling the twist angle and stacking configuration of multilayer\ntwo-dimensional materials is indeed a viable approach to introducing optical chirality into\nintrinsically achiral systems. However, most studies have so far remained limited to theoretical\npredictions and optical measurements. For instance, some works have theoretically predicted\ncircularly polarized responses in twisted multilayer 2D systems,1-3 while others have\nexperimentally observed optical chirality induced by the twist structures.4-6 Nevertheless, there is\nstill a substantial gap between these findings and the realization of efficient circularly polarized\nphotodetection, particularly for achieving high-performance circularly polarized photodetectors.\nThe main difficulties can be summarized as follows:\n1. Translating optical chirality into a measurable photocurrent difference requires a complex\nphotoelectric conversion process that depends on multiple factors, including quantum\nefficiency, carrier mobility, carrier lifetime, and material defects. These dependencies\nmake it nontrivial to achieve efficient circularly polarized photodetection.\n2. If the observed circular polarization response appears only under specific experimental\nconditions (e.g., particular temperature, gate voltage, or wavelength) and is extremely\nweak, it becomes impractical for robust detection applications.\nBased on our survey, we have summarized the representative works that utilize twist\nengineering to realize circular-polarization-dependent photocurrent responses, as shown in the\ntable below.\nTable R3. Summary of the Performance and Operating Conditions of Twist Detectors\nDevice structure (twist Peak Wavelength Detecting Work temperature\nangle) Responsivity &†`' dimensions\nTwisted double bilayer 3.7 V/W 5, 7.7 Intensity, 79K\ngraphene (1.2°) 7 Polarization\nTwisted black phosphorus ~1 mA/W 1.55 Intensity, Room\n(47°) 8 Polarization\nWSe /SiP heterointerface 60 nA/W 1.064 Intensity, Room\n2\n(0° and 90°) 9 Polarization\nThis work 100 mA/W 0.6-3.5 Intensity, Room\nPolarization\nBased on the above survey of twist-engineered designs for circularly polarized light detection,\nwe found that the aforementioned studies mainly remain at the observation stage, lacking the\ncapability to directly read out and distinguish the corresponding signals. Our work aims precisely\nto address this challenge. In other words, simultaneously achieving broadband operation, high\nresponsivity, and high discrimination ratio at room temperature remains an unresolved\nchallenge. This constitutes the key innovation of our work u developing an effective device\ndesign that enables the transition of this phenomenon from mere observation to practical\napplication.\nIf we focus specifically on high-performance circularly polarized photodetection, black\nphosphorus (BP) stands out as a well-recognized material with broad spectral response and high\nintrinsic photoresponsivity. To further evaluate its potential, we have surveyed all polarization-\nsensitive detection schemes based on BP, including those involving twist-engineered structures, as\nsummarized in the table below.\nThese results reveal that while these designs demonstrate excellent linear polarization\ndetection capabilities, it is noteworthy that none of them have achieved circularly polarized light\ndetection. This clearly highlights the breakthrough aspect of our proposed design.\nTable R4 A comparative analysis of the performance metrics for black phosphorus-based detectors\nDevice Wavelength Responsivity Dissymmetry CPL detection\n(+m) (A/W) factor capability\nTwisted black Asp10 5.7 0.15 ' No\nbP/MoS 2 heterojunction11 3.5 0.9 ~15 No\nbP/MoTe 2 heterojunction12 1.63 0.57 - No\nbP homojunction13 1.45 1.06 288 No\nHgCdTe/bp\nheterojunction14 4 0.193 <2 No\nTwisted bp15 1.55 0.007 11.6 No\nThis work 0.6-3.7 0.1 ' Yes\nReferences\n1.Hu, H. et al. Tunable circular polarization responses of twisted black phosphorus metamaterials. Optics Express\n30, 47690-47700 (2022).\n2.Wang, S.-Y. et al. Tunable Optical Rotation in Twisted Black Phosphorus. The Journal of Physical Chemistry\nLetters12, 4755-4761 (2021).\n3.Wu, B.-Y., Shi, Z.-X., Wu, F., Wang, M.-J. & Wu, X.-A* LgebaZ V[\\eT_\\gl \\a gj\\fgXW U\\_TlXe ‚-MoO3. Chinese\nPhysics B31, 044101 (2022).\n4. Shen, J.; Zhu, H.; Sun, X.; Chen, H.; Ji, C.; Li, W.; Kong, W., Van der Waals Assembly of Multilayer Twisted\nTransition Metal Dichalcogenides with Controllable Chirality. Advanced Functional Materials 2025, 35 (41),\n2504859.\n5. Ma, C.; Huang, C.; You, Y.; Liu, H.; Ding, Z.; Ding, M.; Liu, C.; Zhang, J.; Li, G.; Sun, Z.; Wu, S.; Ma, C.;\nWang, E.; Hong, H.; Liu, K., Phase Matching of High Harmonic Generation in Twisted van der Waals Crystals.\nPhysical review letters 2025,135 (16), 166902.\n6. Wang, S.-Y.; Li, D.-K.; Zha, M.-J.; Yan, X.-Q.; Liu, Z.; Tian, J., Tunable Optical Activity in Twisted Anisotropic\nTwo-Dimensional Materials. ACS nano 2023,17 (16), 16230-16238.\n7. Ma, C.; Yuan, S.; Cheung, P.; Watanabe, K.; Taniguchi, T.; Zhang, F.; Xia, F., Intelligent infrared sensing\nenabled by tunable moiré quantum geometry. Nature 2022, 604 (7905), 266-272.\n8.Xiong, Y.; Wang, Y.; Zhu, R.; Xu, H.; Wu, C.; Chen, J.; Ma, Y.; Liu, Y.; Chen, Y.; Watanabe, K.; Taniguchi, T.;\nShi, M.; Chen, X.; Lu, Y.; Zhan, P.; Hao, Y.; Xu, F., Twisted black phosphorustbased van der Waals stacks for\nfiber-integrated polarimeters. Science Advances 2022,8 (18), eabo0375.\n9.Duan, S.; Qin, F.; Chen, P.; Yang, X.; Qiu, C.; Huang, J.; Liu, G.; Li, Z.; Bi, X.; Meng, F.; Xi, X.; Yao, J.; Ideue,\nT.; Lian, B.; Iwasa, Y.; Yuan, H., Berry curvature dipole generation and helicity-to-spin conversion at symmetry-\nmismatched heterointerfaces. Nature nanotechnology 2023,18 (8), 867-874.\n10. Wang, F. et al. Multidimensional detection enabled by twisted black arsenictphosphorus homojunctions.\nNature Nanotechnology19, 455-462 (2024).\n11.Bullock, J. et al. Polarization-resolved black phosphorus/molybdenum disulfide mid-wave infrared photodiodes\nwith high detectivity at room temperature. Nature Photonics12, 601-607 (2018).\n12.Tian, R. et al. Chip-integrated van der Waals PN heterojunction photodetector with low dark current and high\nresponsivity. Light: Science & Applications11, 101 (2022).\n13.Wu, S. et al. Ultra-sensitive polarization-resolved black phosphorus homojunction photodetector defined by\nferroelectric domains. Nature Communications13, 3198 (2022).\n14. Jiao, H. et al. HgCdTe/black phosphorus van der Waals heterojunction for high-performance polarization-\nsensitive midwave infrared photodetector. Science Advances8, eabn1811 (2022).\n15.Xiong, Y. et al. Twisted black phosphorustbased van der Waals stacks for fiber-integrated polarimeters. Science\nAdvances8, eabo0375 (2022).\nAuthor action 1: We have highlighted the novelty and application-oriented contributions of this\nwork in the Introduction, marked in red, and added a series of comparisons with other studies\nregarding performance metrics and implementation strategies in the supplementary tables.\nComment 2. The authors claim that this work satisfies multispectral detection requirements in\ncomplex scenarios, but the results show that it only achieves a wide spectral response and lacks\nmultispectral detection capabilities. This is confusing.\nAuthor Reply 2: PX TcceXV\\TgX g[X eXi\\XjXeyf iT_hTU_X VbeeXVg\\ba* AXeX( jX `T\\a_l ceXfXag g[X\nwide spectral detection results, which are indeed distinct from the characteristics of multispectral\ndetection:\nAspect Wide-spectral Detection Multispectral Detection\nThe detector responds to a continuous and\nThe detector can measure optical responses\nDefinition wide spectral range (e.g., visibletnear\nat multiple discrete spectral bands.\ninfrared).\nTo extendg[XWXgXVgTU_XjTiX_XaZg[eTaZX&vfXX To resolve different wavelength\nGoal\nj\\WXew'* Vb`cbaXagf&vfXXV_XTeXew'*.\nSpectral Response The response curve is broad and smooth, The response curve includes multiple\nFeature usually with one wide peak. discrete bands or channels.\nA single detector unit that covers a broad Multiple filters, materials, or pixel\nTypical Structure\nwavelength range. arrays that form separate channels.\nAspect Wide-spectral Detection Multispectral Detection\nA single integrated signal, representing total Multi-channel signals, each corresponding\nOutput Signal\nintensity. to a distinct spectral band.\nTypical Broadband imaging, white-light detection, solar Remote sensing, biomedical imaging,\nApplications radiation measurement. material analysis, color discrimination.\nBoth concepts concern spectral response: wide-spectral detection emphasizes range, while\nmultispectral detection emphasizes resolution. In practice, multispectral devices often rely on\nbroadband-responsive materials combined with spectral separation strategies. We will carefully\ntake this distinction into account.\nAuthor action 2: We have revised all statements related to Wide-spectral Detection throughout\nthe manuscript to ensure their accuracy.\nComment 3. Judging from the optical photos of the device, aUR NbaU\\_i` P\\[a_\\Y \\cR_ aUR V[aR_SNPR\nis very rough, and it is difficult to ensure that these uncontrollable factors will have a negative\nimpact on the device performance noise.\nAuthor Reply 3: We sincerely thank the reviewer for raising this important point. The challenge\nof achieving precise alignment and bubble-free interfaces in the fabrication of stacked 2D\nmaterials is indeed a significant hurdle, which we have addressed through a carefully developed\ntransfer and contact methodology. Most of the bubbles observed in the optical microscope images\nin the main text were introduced during the top-gate fabrication. The microscopy image of the\nthree-layer BP stack is shown in Figure R1.3b, which clearly indicates a relatively clean surface.\nTherefore, these bubbles are unlikely to significantly affect the generation or measurement of\ninterlayer CPGE.\nTo ensure high-precision layer stacking and reliable electrical contacts, we employed the\nfollowing approach:\nFirst, we developed a custom high-precision transfer system. The rotation motor integrated\n\\agb bhex:aZjX\\ygeTafYXe fgTZXT__bjf Ybe TVVheTgXTaZh_TeVbageb_( XaTU_\\aZgj\\fg TaZ_Xfj\\g[Ta\nuncertainty of only ±0.1°.\nSecond, we adopted a layer-by-layer van der Waals pick-up technique, as illustrated in Reply\nFigure R3.1. Using a glass slide/PDMS/polycarbonate stamp combination, we are able to pick up\nindividual black phosphorus (BP) flakes, precisely control their orientation, and stack them\ngradually to minimize interfacial bubbles (Figure R3.1b).\nFor the electrical contacts, we pre-patterned bottom electrodes (Cr/Au: 2/30 nm) onto the\nsubstrate prior to transfer (Figure R3.1a). The BP layers were then transferred directly onto these\nelectrodes. To ensure ohmic contact quality, an additional layer of graphite was applied over the\ncontact area, serving simultaneously as both a top gate and a contact gate, as shown in Figure\nR3.1d.\nFigure R3.1Twist trilayer black phosphorusFabrication process\nAuthor action 3: To avoid any misunderstanding, we have replaced the microscopy image in the\nmain text with the original tri-layer black phosphorus stacking image to better demonstrate the\ncleanliness of the sample. Besides, we have added the relevant descriptions to the Methods\nsection of the main text and marked them in red.\nComment 44.. JUR QRcVPRi` _R`]\\[`R a\\ OYNPXO\\Qf _NQVNaV\\[ V` NY`\\ b[`NaV`SNPa\\_f* JUR OYNPXO\\Qf\nresponsivity is an order of magnitude lower than the laser responsivity. What accounts for this\ndiscrepancy? The test setup lacks a filter. Therefore, when exposed to a blackbody temperature\nexceeding 750K, the wavelength of light emitted is primarily within the visible spectrum.\n=b_aUR_Z\\_R( aUR QRcVPRi` ]U\\a\\Pb__R[a `dVaPUV[T PUN_NPaR_V`aVP` V[QVPNaR V[`R[`VaVcVay to\nblackbody radiation.\nAuthor Reply4: PX TcceXV\\TgX g[X eXi\\XjXeyf dhXfg\\ba TaW cebi\\WX g[X Yb__bj\\aZ V_Te\\Y\\VTg\\baf6\n11.. M[X eXfcbaf\\i\\gl bY -Ž:+P VbeeXfcbaWf gb ?\\ZheX 0U \\a g[X `T\\a gXkg &T_fb f[bja UX_bj\nin Figure R3.2b), measured with the device operating in photoconductive mode under\napplied bias. This test was intended to demonstrate that our multi-electrode configuration\n(Figure R3.2b) allows for flexible connections depending on the detection requirements,\nenabling either high-gain or high on/off ratio polarization detection. M[X ,*-Ž:+P\nresponsivity under blackbody radiation was obtained under zero bias with the top-layer to\nbottom-layer BP connection, which is used for bipolar circularly polarized light detection.\nFigure R3.2 a, A planar schematic diagram of the twist-stacked black phosphorus. The two ends of the\ntop b-p are labeled A and B, the two ends of the middle b-p are labeled C and D, and the two ends of\nthe bottom b-p are labeled E and F. b, The source-drain current of the C-D intra-layer under different\nwavelength illuminations as a function of bias voltage. The subfigure shows the corresponding\nvariation pattern of the chopped signal.\n2. Blackbody radiation is a broadband light source and is commonly used as a detection\nstandard for practical applications to demonstrate the infrared detection performance of\nc[bgbWXgXVgbef* M[\\f TccebTV[ T__bjf hf Xg XiT_hTgX g[X WXi\\VXyf eXfcbaf\\i\\gl gb jXT^\nradiation across a broad spectral range.\nMb TWWeXff g[X eXi\\XjXeyf VbaVXea eXZTeW\\aZ j[Xg[Xr our detection is limited to the\nvisible spectrum, we note that the results in Figures 3 and 4 of the main text were\nbUgT\\aXW haWXe -11,Ža` TaW .3,,Ža` \\aYeTeXW \\__h`\\aTg\\ba* :WW\\g\\baT__l( jX [TiX\nsupplemented our study with measurements in the mid-infrarXW eTaZX &n/*3Žs`' hf\\aZ T\nquantum cascade laser, as shown in Figure R3.3. These results confirm that the device\nexhibits high responsivity and circular polarization discrimination across the infrared\nspectrum.\nFigure R3.3 Mid-infrared circularly polarized light (3.7 µm) photoresponse measurements of\nthe device\n3. Mb TWWeXff g[X eXi\\XjXeyf VbaVXeaf eXZTeW\\aZ bhe WXi\\VX cXeYbe`TaVX( jX Vb`cTeXW \\g\nacross multiple dimensions. A high-quality circularly polarized light (CPL) detector\nrequires a large circular polarization discrimination ratio, as well as high responsivity and\na broad detection bandwidth. Based on current research, the mainstream photonics-based\napproaches for CPL detectors can be divided into two major categories: The first\napproach relies on materials with chiral molecular structures to enable CPL detection in\nthe visible spectrum. The second popular method involves the use of artificial plasmonic\nstructures for CPL detection within specific spectral bands. However, these methods\nprimarily focus on enhancing circular dichroism and fall short of meeting the demands for\nmultispectral detection under complex scenarios. However, both approaches primarily\nfocus on enhancing circular dichroism and generally do not meet the requirements for\nmultispectral detection in complex scenarios.\nSimultaneously achieving high discrimination ratio, high responsivity, and broadband\noperation remains a significant challenge. Our device, in comparison, demonstrates\nremarkable performance across all three metrics, representing a notable advancement in\nCPL photodetector design, as shown in Figure R3.4.\nFigure R3.4 Current status and key challenges in the research of circularly polarized light\ndetectors.\nIn addition, we have also compared our device with commercially available\ndetectors as Table R5, and our device shows certain advantages in specific performance\nmetrics.\nTable R5 Comparison with typical infrared detectors.\nNo Description Wavelength Peak Bias Ref. (with\n(†m) Responsivity Voltage hyperlink)\n(V/W)\nphotodiode Thorlabs\nphotovoltaic Hamamatsu\ndetector\nphotovoltaic Thorlabs\ndetector\ndetector Thorlabs\ndetector Hamamatsu\n4710\nstacking\n3\nb-p Black body 3.2710\nAuthor action 4: We have added the additional mid-infrared measurements (Figure R3.5) to\nSupplementary Fig. 3-1 and included a performance comparison of this work in the\nSupplementary Information.\nFigure R3.5. The absorption spectrum and mid-infrared circularly polarized light (3.7 µm)\nphotoresponse measurements of the device"}, {"round": 2, "reviewer_comments": {"reviewer_1": "I reviewed the revised manuscript. And I think all of my questions have been properly addressed.", "reviewer_2": "The authors have addressed all of the issues raised by the reviewers and revised the paper accordingly, and thus, the quality of the paper is significantly improved. I recommend publication.", "reviewer_3": "I do see significant improvement in this version, and many of the specific descriptions are quite objective. Therefore, I can recommend that this article be accepted."}, "author_response": ""}]

Decision letter