bluuebunny/crossref_metadata_2025 huggingface dataset:
Intertemporal Price Discrimination via Randomized Promotions
Authors: Chen Hongqiao , Hu Ming , Wu Jiahua
Published: March 2023

Problem definition: The undesirable but inevitable consequence of running promotions is that consumers can be trained to time their purchases strategically. In this paper, we study randomized promotions, where the firm randomly offers discounts over time, as an alternative strategy of intertemporal price discrimination. Methodology/results: We consider a base model where a monopolist sells a single product to a market with a constant stream of two market segments. The segments are heterogeneous in both their product valuations and patience levels. The firm precommits to a price distribution, and in each period, a price is randomly drawn from the committed distribution. We characterize the optimal price distribution as a randomized promotion policy and show that it serves as an intertemporal price discrimination mechanism such that high-valuation customers would make a purchase immediately at a regular price upon arrival, and low-valuation customers would wait for a random promotion. Compared against the optimal cyclic pricing policy, which is optimal within the strategy space of all deterministic pricing policies, the optimal randomized pricing policy beats it if low-valuation customers are sufficiently patient and the absolute discrepancy between high and low customer valuations is large enough. We extend the model in three directions. First, we consider the case where a portion of customers are myopic and would never wait. We show that the existence of myopic customers is detrimental to the firm’s profitability, and the expected profit from an optimal randomized pricing policy decreases as the proportion of myopic customers in the population increases. Second, we consider Markovian pricing policies where prices are allowed to be intertemporally correlated in a Markovian fashion. This additional maneuver allows the firm to reap an even higher profit when low-valuation customers are sufficiently patient by avoiding consecutive promotions but, on average, running the promotion more frequently with a smaller discount size. Lastly, we consider a model with multiple customer segments and show that a two-point price distribution remains optimal, and our conclusion from the two-segment base model still holds under certain conditions that are adopted in the literature. Managerial implications: Our results imply that the firm may want to deliberately randomize promotions in the presence of forward-looking customers.

Funding: This work was supported by the National Natural Science Foundation of China [Grant 72201124], the Natural Sciences and Engineering Research Council of Canada [Grants RGPIN-2015-06757 and RGPIN-2021-04295], and the Youth Project of the Humanities and Social Science Foundation of the Ministry of Education of China [Grant 22YJC630006].

Supplemental Material: The online appendix is available at https://doi.org/10.1287/msom.2023.1194 .
Starting to talk
Authors: Weinstein Nicole
Published: March 2023

How can the learning environment and the resources in it promote effective communication? Nicole Weinstein goes back to basics
The plants in my street
Authors: Mountain Julie
Published: March 2023

Nettles are wonderful, says Julie Mountain, who is going to try and convince you to love them as much as she does this March
Wellbeing
Authors: O'Sullivan June
Published: March 2023

June O'Sullivan, CEO of London Early Years Foundation, considers why building resilience is positive for children's wellbeing
COVID-19 Related Stress and Life Satisfaction in Turkish Undergraduates: A Serial-Parallel Mediation Model
Authors: Kırıkkanat Berke
Published: March 2023

One of the life areas under the impact of the COVID-19 pandemic is university education. As it becomes more prevalent with its various versions, it shapes undergraduates' psychological well-being profoundly. It is necessary to understand how COVID-19-related stress impacts their mental life. The purpose of the study was to examine whether COVID-19 burnout and cognitive emotion regulation had mediating roles in the relationship between COVID-19-related stress and life satisfaction. Three hundred sixty-four Turkish undergraduates participated in the study. Mediational analyses showed that both adaptive and maladaptive cognitive emotion regulation had interplaying roles in the link between COVID-19-related stress and life satisfaction, unlike COVID-19 burnout. Yet, COVID-19-related stress indirectly affected life satisfaction since COVID-19 burnout increased maladaptive cognitive emotion regulation strategies while decreasing adaptive ones concurrently. The findings are crucial for mental health professionals whose aim is to develop necessary psychological interventions for undergraduates to increase their life satisfaction levels during the COVID-19 pandemic.
Design and Experiment of a Situ Compensation System for Miss-Seeding of Spoon-Chain Potato Seeders
Authors: Qiu Zhaomei , Ma Tengfei , Jin Xin , Xing Fan , Ji Jiangtao , Shi Gaoxiang
Published: March 2023

Highlights

A situ compensation system for miss-seeding of spoon-chain potato seeders was designed.

Human/computer interaction system for visual quality monitoring of spoon chain potato planting.

The miss-seeding problem of spoon-chain potato seeder was improved.

Design of miss-seeding compensation device for spoon chain potato seeder.

Abstract. To address the problem of miss-seeding in spoon chain potato seeders, a set of in situ compensation systems for miss-seeding of spoon chain potato based on compensation technology was designed. The system consists of three parts: a miss-seeding detection system, a miss-seeding compensation system, and a visual monitoring system that can realize real-time feedback and reseeding of miss-seeding. The actual seeding situation of the compensated potato will be visually monitored by the industrial camera, and the seeding count will be conducted. The real-time seeding screen is displayed on the upper computer. The design of miss-seeding detection device, in situ reseeding device, structure design of miss-seeding in situ compensation system based on PLC visual monitoring human-computer interaction system were carried out. Then the potato miss-seeding compensation bench test and field test were carried out. Field experiments showed that when the seeding rate of the potato seeder was 0.3 to 0.7 m/s, the detection accuracy of the miss-seeding detection system could reach more than 98.5%, and the miss-seeding rates after reseeding were all below 5%. The visual monitoring effect of seeding quality was good, and the counting accuracy was 99.5%. The designed in situ compensation system has stable working state, light structure, high compensation and monitoring accuracy, and can solve the problem of miss-seeding in the operation of spoon and chain potato seeders. Keywords: Cut potato, In situ reseeding, Miss-seeding detection, Spoon-chain type.
Using Nonstationary Depth-Frequency Curves to Characterize Local Precipitation Trends
Authors: Marali Kalra , Cibin Raj
Published: March 2023

Highlights

Design storms should incorporate nonstationarity under changing climate scenarios.

Three generalized extreme value distributions were fitted to represent nonstationarity for local precipitation analysis.

The nonstationary models proposed in this study perform well at sites with strong precipitation trends.

Abstract. As climate change advances, the stationarity assumption that governs traditional precipitation analysis is becoming untenable. Studies that incorporate nonstationarity typically use global circulation model (GCM) projections to determine the magnitude and direction of expected precipitation changes. However, the high computational costs and the coarse spatial resolution of GCMs make this method unsuitable for local precipitation analysis. In this study, nonstationarity is represented by a precipitation probability distribution with time-varying parameters. Three generalized extreme value (GEV) distributions are fitted: (1) the shift model, where the GEV location parameter varies linearly with time, (2) the stretch model, where the GEV location and scale parameters both vary linearly with time, and (3) the stationary model, a time-invariant distribution provided for the purpose of comparison. This procedure is applied to 24-h annual maximum precipitation records for ninety years (1900-1989) at five long-term measuring sites in Pennsylvania. Results varied among the five sites, suggesting that localized climate effects can cause precipitation differences at a small spatial scale. No significant nonstationarity was detected in two of the five locations. In three locations, however, increases in GEV location and scale combined to create a substantial, though not always significant, rise in the frequency of extreme precipitation. These trends were extrapolated forward over 30 years (1990-2019) and compared with an observed distribution for that year. The nonstationary models appeared to perform better at sites with stronger precipitation trends, which suggests a simple procedure for selecting sites where nonstationary analysis is most needed. Keywords: Climate change, Design storm, Generalized extreme value, Nonstationarity.
Improving the DC-Link Voltage of DFIG Driven Wind System Using Modified Sliding Mode Control
Authors: Hiremath Ravikiran , Moger Tukaram
Published: March 2023

The grid-connected doubly fed induction generator (DFIG) driven wind turbine (WT) system encounters voltage fluctuations due to severe grid faults. The rise in DC-link voltage imbalances the system under voltage sag condition. The system’s protection should ensure that the WT generator meets the grid requirements through a low voltage ride through (LVRT) technique. This paper proposed the modified 2nd order sliding mode (MSOSM) control with gain added super twisting algorithm (GAST) for LVRT enhancement under voltage sag. This controller adds the low positive gains to the switching functions of the super twisting (ST) algorithm. As a result, it maintains the proper variation margins and constant DC-link voltage of the WT-DFIG system under grid fault. The MSOSM controller suppresses the chattering effect, achieves better zero convergence, and eliminates the coordinate transformations. Moreover, the performance of the proposed controller is compared with existing controllers in the literature with the help of MATLAB/SIMULINK. The hardware-in-loop (HIL) validates these simulation results performed on the OPAL-RT setup. Based on the studies, it is found that the proposed controller enhances the performance of the WT-DFIG system under transient conditions.
A Novel Opposition-Based Border Collie Optimization Approach for Fault Detection in Solar Photovoltaic Array
Authors: Chandrasekharan Sowthily , Subramaniam Senthilkumar , Bhoreddy Malakonda Reddy , Veerakgoundar Veeramani
Published: March 2023

Solar photovoltaic systems installed in outdoor environments are susceptible to faults and partial shading, which leads to reduction in the production of maximum power. The conventional protection units are unable to detect the types of faults due to non-linear characteristics and they result in fire hazards and reduced system efficiency. In this paper, a fault detection method based on Multiclass Support Vector Machine (MSVM) is proposed to detect different faults like line-ground (L-G), line-line (L-L), and partial shading. The array voltage, array current and irradiance are used to detect the line-line and partial shading under different irradiation conditions. The novel Opposition-based Border Collie Optimization (OBCO) algorithm is used to improve the accuracy of fault classification by optimizing the hyper-parameters of MSVM. A 1.6 kW, 4 × 4 solar photovoltaic array is developed, and the fault conditions are experimentally tested to validate the proposed algorithm. The experimental results show that the proposed MSVM-OBCO fault detection algorithm has higher accuracy compared to that of the existing classification algorithms such as k-nearest neighbor, Naïve Bayes, Decision Tree and Random Forest.
Optimal Placement and Sizing of Renewable and Non-Renewable Resources in Smart Grid
Authors: Chippada Devisree , Reddy M. Damodar
Published: March 2023

Distributed Generators (DGs) play a key role in existing power distribution networks together with significant innovations in smart grid technology. It is now more essential to evaluate the various types of DGs within the system. Renewable energy types of DGs such as PV and wind promise low emissions and abundant availability. When it comes to the installation of DG, the size, location, and type of DG should be given high importance because improper placement of DG units leads to reducing the benefits of the distribution system and even endangers the entire system operation. If DG size exceeds a certain value limit, power loss at that bus becomes negative. This situation must be avoided. As a result, optimal DG placement aids in the reduction of losses, improvement of voltage profiles, reliability, and overall system efficiency. Considering this, in this paper, a Simultaneous Particle Swarm Optimization (PSO) algorithm is implemented for placement allocation and sizing of multiple types and multiple numbers of DGs in power distribution systems with the objectives of minimization of active and reactive power loss and enhanced voltage profile. Along with the meta-heuristic optimization algorithm, sensitivity techniques such as index vector, loss sensitivity factor, and voltage stability margin methods have been analysed. The outcomes are obtained using the aforementioned sensitivity-related methods on the IEEE 15, 33, 69, and 85-radial bus systems and compared with simultaneous PSO for efficacy.
Battery Electric Tractor Powertrain Component Sizing With Respect To Energy Consumption, Driving Patterns and Performance Evaluation Using Traction Motor
Authors: Gade Chandrasekhar Reddy , Sultana W. Razia
Published: March 2023

In this paper sizing the powertrain of battery electric tractor (BET) including major farming implements are investigated for various real world driving patterns. Powertrain components are modelled using torque-load characteristics which are function of speed, acceleration, plowing implement and depth of plowing and texture of the soil. Effect of load variations on powertrain performance and energy consumption are also explained in detail. In this powertrain design major farming implements like chisel plough, mould board plough, field cultivator, sweep plough are considered. Tractor hauling a trailer carrying goods with 2000 kg weight is also considered for powertrain design. Typical operating velocities of 18, 15 and 25 kmph are taken for sand, tillage and asphalt surfaces respectively for tractor trailer applications and 7 kmph for plowing applications. The dynamic model of the powertrain is modelled in MATLAB/SIMULINK. PMSM is selected as a traction motor and its performance is evaluated in MATLAB/SIMULINK. Same has been verified using real-time Hardware in loop (HIL) simulator with help of OPAL-RT (OP5700).
Production of research in Southern Africa from a political ethics of care perspective: a scoping review and reflection
Authors: Kelly Gabrielle , Sebego Miriam
Published: March 2023

In this article, we present a scoping review of the evidence and discussions in the extant literature on long-term care for older people in Southern Africa, focusing particularly on patterns of knowledge production in the region. Findings indicate that while the number of publications has increased over recent years, empirical research in countries outside of South Africa is extremely sparse and underfunded, and there is no clear research agenda. Drawing on a political ethics of care perspective, we reflect on the lack of attention to issues of care and the positioning of care for older people within societies in the region.
Are "Modal Adverbs" automatically Modal Markers? The Case of French "Certainement" with its Epistemico-Modal and its Evidential Use
Authors: Dendale Patrick
Published: March 2023

The French adverb certainement (‘certainly’) is labelled a “modal adverb”. It has two (sentence adverb) uses according to the literature, called “strong modal use” and “weak modal use”. The strong modal use is indeed strong (epistemico-)modal in that it indicates total certainty, whether subjective or intersubjective. What is called its “weak modal use” is shown to be an evidential use. It indicates primarily that the content qualified by the adverb results from a non-monotonic inference, performed by the speaker, whose conclusions are plausible, defeasible, and thus never totally certain. This is due to the presence of an evidential-inferential component in its meaning. As for the so-called weak modal element of “probability” in its meaning, we reanalyse it as “non- certainty” and argue it is an element of utterance meaning, a property of quasi-assertions to which non-monotonically inferred content gives rise. Finally, we claim that the adverb also has a meaning component that we call “epistemic posture of certainty”, shown to be different from epistemic modality. On the basis of three parameters and their values, we show how certainementcan be interpreted, in a series of contextual configurations, either as an instance of its epistemico- modal use or of its evidential use.
Evidentiality in Spoken Catalan. The Evidential Marker "diu que"
Authors: Antolí Martínez Jordi M. , Sentí i Pons Andreu
Published: March 2023

This study deals with an Catalan evidential marker without a written tradition, but mainly an oral one: diu que (‘(s)he.says.that’, ‘it is said that’), a Romance correlate for dizque (Spanish) or dice che (Italian) (cf. Travis 2006, Cruschina 2015, Alcázar 2018). The spoken, dialectal and, to some extent, residual nature of this marker forces us to search for different sources in order to approach it. The study focuses on the oral recordings of Museu de la Paraula [Word Museum] —an ethnological archive with monological spoken texts— will be completed with the examination of the first results of the colloquial corpus Parlars —a dialectal and informal corpus with monological and dialogical spoken texts. The analysis of diu que and the corpus data show a partially grammaticalized construction with a reportative evidential value. A mirative extension can be also found, but not a pure epistemic meaning. Also, the rise of diu que has been seen as an example of grammatical constructionalization with a tendency towards more subjective meanings, from a quotative strategy to a reportative evidential marker. Related markers such asque diu que or the conventional formula to begin tales això diu que era have been attested.
Aspectos cognitivos y construcciones de la evolución semántica del verbo "tocar"
Authors: Fernández Jaén Jorge
Published: March 2023

Este artículo presenta un análisis diacrónico del verbo tocar realizado desde los parámetros de la semántica cognitiva diacrónica, tal y como los expone Geeraerts (1997). Demostraremos que la intrincada polisemia que tocar muestra en la actualidad es el resultado de la expansión semasiológica del verbo a lo largo de los siglos, expansión que se origina en el primer significado prototípico del verbo (GOLPEAR) y que se desarrolla a partir de diversas reformulaciones en sus esquemas de imagen, de múltiples proyecciones metafóricas y metonímicas y de la actuación de la dinámica de fuerzas (Talmy 1988, 2000). Asimismo, probaremos que la motivación de todo el desarrollo diacrónico de tocar está regulada por la conciencia corporal del hablante (de acuerdo con lo que predice el principio cognitivo de indexicalidad) y que las construcciones sintácticas del verbo reproducen icónicamente dicha conciencia corporal.
Una aproximación al estudio de los eventos de movimiento metafórico desde la tipología semántica y el género
Authors: Ibarretxe-Antuñano Iraide , Caballero Rodríguez Rosario
Published: March 2023

Talmy (1991, 2000) clasifica las lenguas en dos tipos, de marco-­‐‑verbal y marco de satélite, según dónde codifiquen el componente del Camino en la expresión verbal de un evento de movimiento. Las diferencias de codificación entre estas lenguas se reflejan en el uso en línea de los hablantes, lo que hace que su estilo retórico sea diferente aunque describan un mismo evento (Slobin 1996). La mayoría de los estudios en este campo, se ha centrado, por un lado, en el movimiento físico y, por otro lado, ha tomado como base empírica datos con un contexto muy limitado. Este artículo analiza la lexicalización de los eventos de movimiento metafóricos en textos pertenecientes a géneros específicos. Partiendo de un corpus de 600.000 palabras que incluye reseñas de arquitectura, tenis y catas de vino en español e inglés, se investiga (a) si las diferencias de lexicalización y de estilo retórico entre el español y el inglés en los eventos de movimiento planteadas en estudios anteriores se mantienen en géneros no narrativos y, (b) si la idiosincrasia de cada género tiene consecuencias tipológicas que afectan a la creatividad y la expresividad en la descripción de los eventos de movimiento metafóricos.
Ordered photonic colloidal suspensions
Authors: Jiménez-Villar Ernesto , Martins Weliton S. , Wetter Niklaus U.
Published: March 2023

Ordered photonic structures (photonic crystals) have seen increasing
interest in recent years due to their potential applications, which
depend on fabrication technologies suitable for mass production. In
this paper, we studied by light diffraction the order in photonic
colloidal suspensions composed by core-shell (TiO2@Silica) nanoparticles suspended in ethanol
and water solutions. Light diffraction measurements show order in
these photonic colloidal suspensions, being stronger in ethanol
compared with suspensions in water. Strong and long-range Coulomb
interaction explains the order and correlation in the scatterers’ (TiO2@Silica) position, which favors significantly
the interferential processes as localization of light.
Moiré effect in multilayered 3D lattice
Authors: Saveljev Vladimir
Published: March 2023

The moiré effect was observed in a multilayered three-dimensional (3D)
structure with voxels at the points of a simple cubic lattice. Visual
corridors result from the moiré effect. The frontal camera’s corridors
appear at distinctive angles with rational tangents. We analyzed the
effects of distance, size, and thickness. We carried out computer
simulation and physical experiments; both confirmed the distinctive
angles of the moiré patterns for the three camera locations near the
facet, edge, and vertex. The conditions for the moiré patterns to
appear in the cubic lattice were formulated. The results can be used
in crystallography and in minimization of the moiré effect in
LED-based volumetric 3D displays.
Mathematical model of potential distribution in a pinned photodiode of an indirect time of flight CMOS image sensor
Authors: Shi Xiaolin , Li Xinyao , Mao Yujia , Ren Ying , Zhang Ruixin , Zhao Chenyang , Xu Jiangtao , Nie Kaiming , Gao Zhiyuan
Published: March 2023

This paper focuses on the rapid charge transfer of lock-in pixels in time of flight 3D image sensors. Through the principal analysis, a mathematical model of potential distribution in a pinned photodiode (PPD) in different comb shapes is established. Based on this model, the influence of different comb shapes on the accelerating electric field in PPD is analyzed. The semiconductor device simulation tool SPECTRA is applied to verify the effectiveness of the model, and the simulation results are analyzed and discussed. When the width of comb tooth is in narrow and medium range, the potential changes more obviously with the increase of comb tooth angle α, whereas the potential becomes stable even if the comb tooth angle α increases sharply with the wide comb tooth width. The proposed mathematical model contributes to instructing the design of pixel transferring electrons rapidly and resolving image lag.
Application of acquiring region of interest based on the YOLOv5 model in terahertz digital holography
Authors: Cheng Keyang , Li Qi
Published: March 2023

The imaging process of terahertz in-line digital holography is susceptible to environmental interference, and it is difficult to obtain high-quality images and image segmentation results. The challenge can be better handled by using the region of interest (ROI) condition to improve the image quality of the object region and reduce the interference of peripheral noise. In this paper, for two-dimensional 2.52 THz in-line digital holography, a method to add a variety of real backgrounds in the simulation scene is proposed, and through this method, a sufficient amount of close-to-real-scene images are produced to train the YOLOv5 model. The object ROI is extracted by the YOLOv5 model (YOLOv5-ROI). Based on the region, a new, to the best of our knowledge, support-domain-constrained phase retrieval algorithm (YOLOv5-ROI-SPRA) and an image segmentation method combined with the Otsu method (YOLOv5-ROI-Otsu) are proposed, respectively. The better results show that the expected purpose is achieved.
Modeling of a second harmonic spectrum in passive phase demodulation
Authors: Ruan Bowen , Zeng Xin , Feng Yan
Published: March 2023

Spectral compression by passive phase demodulation provides an
effective way to obtain a high-power single-frequency second harmonic
(SH) laser. In this method, a single-frequency laser is broadened by
(0, π) binary phase modulation for
stimulated Brillouin scattering suppression in a high-power fiber
amplifier and compressed to single frequency after frequency doubling.
The effectiveness of compressing is determined by the properties of
the phase modulation system, including the modulation depth, frequency
response of modulation system, and modulation signal noise. A
numerical model is developed to simulate the influence of these
factors on the SH spectrum. The simulation results reproduce the
experimental observation well, including the reduction of the
compression rate at higher-frequency phase modulation, emergence of
spectral sidebands and pedestal.
Latin America Optics and Photonics 2022: introduction to the feature issue
Authors: Gomes Anderson S. L. , de Souza Eunezio Thoroh , Zezell Denise M.
Published: March 2023

The 2022 Latin America Optics and Photonics Conference (LAOP 2022), the major international conference sponsored by Optica in Latin America, returned to Recife, Pernambuco, Brazil, after its first edition in 2010. Held every two years since (except for 2020), LAOP has the explicit objective to promote Latin American excellence in optics and photonics research and support the regional community. In the 6th edition in 2022, it featured a comprehensive technical program with recognized experts in fields critical to Latin America, highly multidisciplinary, with themes from biophotonics to 2D materials. The 191 attendees of LAOP 2022 listened to five plenary speakers, 28 keynotes, 24 invited talks, and 128 presentations, including oral and posters.
Real-time validation of downstream 50G/25G and 50G/100G flexible rate PON based on Miller encoding, NRZ, and PAM4 modulation
Authors: van Veen Doutje , Houtsma Vincent
Published: March 2023

Experimental demonstration is given of a real-time flexible downstream 50 Gb/s passive optical network (PON) mixed with 25 Gb/s or 100 Gb/s signals. 25 Gb/s transmission is enabled by using 25 Gb/s Miller encoding. For back-to-back a lower sensitivity for 25 Gb/s Miller of ∼2.2dB is found relative to 50 Gb/s non-return-to-zero (NRZ). An extended reach of 40 km and up to ∼5dB optical power budget improvement after worst-case 20 km standard single-mode fiber over 50 Gb/s NRZ was shown for 25 Gb/s Miller. It was also shown that optical network units (ONUs) that have 9 dB additional optical received power because they experience a lower optical loss can receive 100 Gb/s four-level pulse amplitude modulation (PAM4) instead of NRZ in a flexible rate PON, which will double the bit-rate to these ONUs. 50 Gb/s NRZ transmission under mixed modulation (50% NRZ and 50% Miller or 50% PAM4) can operate with very low penalty. A power penalty of <0.4dB was found for 50 Gb/s NRZ after worst-case total dispersion (as specified in ITU-T G.9804) when mixed with 25 Gb/s Miller or 100 Gb/s PAM4. For back-to-back there was a smaller penalty of <0.2dB for 50 Gb/s NRZ under mixed modulation. The 25 Gb/s Miller signal spectrum is similar to 50 Gb/s NRZ and 100 Gb/s PAM4, which enables good performance of the real-time clock and data recovery with an integrated adaptive feed-forward-equalizer based equalizer under mixed signal modulation. The increased optical power budget enabled by the 25 Gb/s Miller encoding effectively improves power margins of the high-speed PON and will enable reliable transmission for ONUs deployed with out-of-spec (higher) loss and/or (larger) fiber reach. The additional margin provided by 25 Gb/s Miller encoding will also enable a safe-mode for ONUs that experience out-of-spec scenarios because of faults in the PON fiber network.
Engineering optomechanically induced transparency by coupling a qubit to a spinning resonator
Authors: Burns Jessica , Root Owen , Jing Hui , Mirza Imran M.
Published: March 2023

We theoretically study the spectral properties of a pump–probe driven hybrid spinning optomechanical ring resonator optically coupled with a two-level quantum emitter (QE or qubit). Recently, we have shown [Opt. Express 27, 25515 (2019)OPEXFF1094-408710.1364/OE.27.025515] that in the absence of the emitter, the coupled cavity version of this setup is not only capable of non-reciprocal light propagation but can also exhibit slow and fast light propagation. In this work, we investigate in what ways the presence of a single QE coupled with the optical whispering gallery modes of a spinning optomechanical resonator can alter the probe light non-reciprocity. Under the weak-excitation assumption and mean-field approximation, we find that the interplay between the rotational/spinning Sagnac effect and qubit coupling can lead to enhancement of both the optomechanically induced transparency peak value and the width of the transparency window due to the opening of a qubit-assisted backreflection channel. However, compared to the no-qubit case, we notice that such enhancement comes at the cost of degrading the group delay in probe light transmission by a factor of 1/2 for clockwise rotary directions. The target applications of these results can be in the areas of quantum circuitry and in non-reciprocal quantum communication protocols where QEs are a key component.
Intelligent interior atmosphere lamp system based on quantum dot LEDs for safe driving assistance
Authors: Zhu Chunxiao , Gao Jianqiao , Lu Min , Zhang Yu , Wang Zhenyu , Huang Qizhang , Wu Zhennan , Gao Yanbo , Wang YanPing , Yu William W. , Hu Junhua , Bai Xue
Published: March 2023

A driver safety assisting system is essential to reduce the probability of traffic accidents. But most of the existing driver safety assisting systems are simple reminders that cannot improve the driver's driving status. This paper proposes a driver safety assisting system to reduce the driver's fatigue degree by the light with different wavelengths that affect people's moods. The system consists of a camera, an image processing chip, an algorithm processing chip, and an adjustment module based on quantum dot LEDs (QLEDs). Through this intelligent atmosphere lamp system, the experimental results show that blue light reduced the driver’s fatigue degree when just turned on; but as time went on, the driver’s fatigue degree rebounded rapidly. Meanwhile, red light prolonged the driver's awake time. Different from blue light alone, this effect can remain stable for a long time. Based on these observations, an algorith was designed to quantify the degree of fatigue and detect its rising trend. In the early stage, the red light is used to prolong the awake time and the blue light to suppress when the fatigue value increases, so as to maximize the awake driving time. The result showed that our device prolonged the awake driving time of the drivers by 1.95 times and reduced fatigue during driving: the quantitative value of fatigue degree generally decreased by about 0.2 times. In most experiments, the subjects were able to complete four hours of safe driving, which reached the maximum length of continuous driving at night allowed by China laws. In conclusion, our system changes the assisting system from a reminder to a helper, thus effectively reducing the driving risk.
Mitigating probe pulse deformation in Raman amplification in OTDR fiber sensing systems
Authors: Wang Zepeng , Vandborg Mads Holmark , Joy Tomin , Mathew Neethu Mariam , Grüner-Nielsen Lars , Rishøj Lars Søgaard , Christensen Jesper Bjerge , Jostmeier Thorben , Marx Benjamin , Hill Wieland , Rottwitt Karsten
Published: March 2023

We report the numerical and experimental study of probe pulse deformation in a forward-pumped distributed Raman amplifier on a 40-km standard single mode fiber. Distributed Raman amplification can improve the range of OTDR-based sensing systems, but it could result in pulse deformation. A smaller Raman gain coefficient can be used to mitigate pulse deformation. The sensing performance can still be maintained by compensating for the decrease in the Raman gain coefficient by increasing the pump power. The tunability of the Raman gain coefficient and pump power levels are predicted while keeping the probe power below the modulation instability limit.
Numerical analysis of the ultra-wide tunability of nanofiber Bragg cavities
Authors: Takashima Hideaki , Schell Andreas W. , Takeuchi Shigeki
Published: March 2023

Nanofiber Bragg cavities (NFBCs) are solid-state microcavities fabricated in optical tapered fiber. They can be tuned to a resonance wavelength of more than 20 nm by applying mechanical tension. This property is important for matching the resonance wavelength of an NFBC with the emission wavelength of single-photon emitters. However, the mechanism of the ultra-wide tunability and the limitation of the tuning range have not yet been clarified. It is important to comprehensively analyze both the deformation of the cavity structure in an NFBC and the change in the optical properties due to the deformation. Here, we present an analysis of the ultra-wide tunability of an NFBC and the limitation of the tuning range using three dimensional (3D) finite element method (FEM) and 3D finite-difference time-domain (FDTD) optical simulations. When we applied a tensile force of 200 μN to the NFBC, a stress of 5.18 GPa was concentrated at the groove in the grating. The grating period was extended from 300 to 313.2 nm, while the diameter slightly shrank from 300 to 297.1 nm in the direction of the grooves and from 300 to 298 nm in the direction orthogonal to the grooves. This deformation shifted the resonance peak by 21.5 nm. These simulations indicated that both the elongation of the grating period and the small shrinkage of the diameter contributed to the ultra-wide tunability of the NFBC. We also calculated the dependence of the stress at the groove, the resonance wavelength, and the quality Q factor while changing the total elongation of the NFBC. The dependence of the stress on the elongation was 1.68 × 10−2 GPa/μm. The dependence of the resonance wavelength was 0.07 nm/μm, which almost agrees with the experimental result. When the NFBC, assumed to have the total length of 32 mm, was stretched by 380 μm with the tensile force of 250 μN, the Q factor for the polarization mode parallel to the groove changed from 535 to 443, which corresponded to a change in Purcell factor from 5.3 to 4.9. This slight reduction seems acceptable for the application as single photon sources. Furthermore, assuming a rupture strain of the nanofiber of 10 GPa, it was estimated that the resonance peak could be shifted by up to about 42 nm.
Circular dichroism in a plasmonic array of elliptical nanoholes with square lattice
Authors: Ali Hanan , Petronijevic Emilija , Pellegrini Giovanni , Sibilia Concita , Andreani Lucio Claudio
Published: March 2023

Chiral properties of plasmonic metasurfaces, especially related to different absorption of left and right circularly polarized light leading to circular dichroism (CD), are a research hot topic in nanophotonics. There is often a need to understand the physical origin of CD for different chiral metasurfaces, and to get guidelines for the design of structures with optimized and robust CD. In this work, we numerically study CD at normal incidence in square arrays of elliptic nanoholes etched in thin metallic layers (Ag, Au, Al) on a glass substrate and tilted with respect to the symmetry axes. Strong CD arises in absorption spectra at the same wavelength region of extraordinary optical transmission, indicating highly resonant coupling between light and surface plasmon polaritons at the metal/glass and metal/air interfaces. We elucidate the physical origin of absorption CD by a careful comparison of optical spectra for different polarizations (linear and circular), with the aid of static and dynamic simulations of local enhancement of the electric field. Furthermore, we optimize the CD as a function of the ellipse parameters (diameters and tilt), the thickness of the metallic layer, and the lattice constant. We find that silver and gold metasurfaces are most useful for CD resonances above 600 nm, while aluminum metasurfaces are convenient for achieving strong CD resonances in the short-wavelength range of the visible regime and in the near UV. The results give a full picture of chiral optical effects at normal incidence in this simple nanohole array, and suggest interesting applications for chiral biomolecules sensing in such plasmonic geometries.
Mode-modulation-induced high power dual-wavelength generation in a random distributed feedback Raman fiber laser
Authors: Li Yang , Yao Haoguang , Fan Chenchen , Hao Xiulu , Yao Tianfu , Zhou Pu , Zeng Xianglong
Published: March 2023

An all-fiberized random distributed feedback Raman fiber laser (RRFL) with mode-modulation-induced wavelength manipulation and dual-wavelength generation has been demonstrated, where an electrically controlled intra-cavity acoustically-induced fiber grating (AIFG) is employed to adjust the input modal content at the signal wavelength. The wavelength agility of both the Raman effect and the Rayleigh backscattering in RRFL benefits on broadband laser output in case of broadband pumping. The feedback modal content at different wavelengths can be adjusted by AIFG, and then the output spectral manipulation can be ultimately manifested through the mode competition in RRFL. Under the efficient mode modulation, the output spectrum can be continuously tuned from 1124.3 nm to 1133.8 nm with single wavelength, while ulteriorly the dual-wavelength spectrum can be formed at 1124.1 nm and 1134.7 nm with a signal-noise-ratio of 45 dB. Throughout, the power is beyond 47 W with good stability and repeatability. To the best of our knowledge, this is the first dual-wavelength fiber laser based on mode modulation and the highest output power ever reported for an all-fiberized continuous wave dual-wavelength fiber laser.
Topological edge states in equidistant arrays of lithium niobate nano-waveguides
Authors: Gorbach Andrey V. , Beer Jesper , Souslov Anton
Published: March 2023

We report that equidistant 1D arrays of thin-film lithium niobate
nano-waveguides generically support topological edge states. Unlike
conventional coupled-waveguide topological systems, the topological
properties of these arrays are dictated by the interplay between
intra- and inter-modal couplings of two families of guided modes with
different parities. Exploiting two modes within the same waveguide to
design a topological invariant allows us to decrease the system size
by a factor of two and substantially simplify the structure. We
present two example geometries where topological edge states of
different types (based on either quasi-TE or quasi-TM modes) can be
observed within a wide range of wavelengths and array spacings.
Highly stable, flexible delivery of microjoule-level ultrafast pulses in vacuumized anti-resonant hollow-core fibers for active synchronization
Authors: Yan Chuanchuan , Li Hongyang , Huang Zhiyuan , Wang Xinliang , Liu Donghan , Liu Xingyan , Pan Jinyu , Luo Zhuozhao , Yang Fei , Zheng Yu , Yin Ruochen , Yu Haihu , Leng Yuxin , Song Liwei , Pang Meng , Jiang Xin
Published: March 2023

We demonstrate the stable and flexible light delivery of multi-microjoule, sub-200-fs pulses over a ∼10-m-long vacuumized anti-resonant hollow-core fiber (AR-HCF), which was successfully used for high-performance pulse synchronization. Compared with the pulse train launched into the AR-HCF, the transmitted pulse train out of the fiber exhibits excellent stabilities in pulse power and spectrum, with pointing stability largely improved. The walk-off between the fiber-delivery and the other free-space-propagation pulse trains, in an open loop, was measured to be <6 fs root mean square (rms) over 90 minutes, corresponding to a relative optical-path variation of <2 × 10−7. This walk-off can be further suppressed to ∼2 fs rms simply by using an active control loop, highlighting the great application potentials of this AR-HCF setup in large-scale laser and accelerator facilities.
Nanoantennas for selectively switching on and off under different input phase distributions and wavelengths
Authors: Huang Haiyang , Gan Fengyuan , Zhou Yi , Lan Dun , Shang Xiangshuo , Li Wei
Published: March 2023

Optical nanoantennas, as devices connecting free-space light and on-chip light, are important components of integrated photonic circuits. They are often used as optical couplers, and in optical routine of intermediate layers of IC chips. To have more degrees of freedom to manipulate the light scattering, we design a novel optical nanoantenna composed of subwavelength silicon pillars. The antenna can exhibit on and off scattering states under different input optical modes and exhibit opposite on-off characteristics at different wavelengths. The antenna is small in size and flexible in design, and has the potential to build a more flexible 3D optical link for photonic integrated circuits.
Short pulses from a gain-switched quantum cascade laser
Authors: Täschler Philipp , Miller Lucius , Kapsalidis Filippos , Beck Mattias , Faist Jérôme
Published: March 2023

The picosecond carrier dynamics observed in quantum cascade lasers (QCLs) poses a fundamental obstacle for the formation of intracavity pulses. On the other hand, the ultrafast gain response makes the QCL ideally suited for high frequency modulation of its pump current. In this work, we leverage this property and use short electrical excitations to generate 33 ps optical pulses with up to Watt level peak power. We ensure lasing on a single resonator mode via optical injection seeding. The resulting pulses are characterized in both time and frequency domains using an optical sampling method in combination with a spectrometer. We interpret the obtained results using laser rate equations. The results presented in this work open new pathways for the generation of highly tunable, high power mid-infrared pulses from a monolithic source.
Refractive index improvement of commercial chalcogenide glasses by external doping with Ag and Pb
Authors: Liu Zijun , Li Jialin , Xia Kelun , Gu jierong , Zhang Jingwei , Zheng Wenfeng , Yang Zhiyong , Shen Xiang
Published: March 2023

The refractive index of commercial chalcogenide glasses (ChGs) available in the market is generally 2.4 to 2.7, which is relatively low and has huge room for improvement. In this paper, different ratios of Ag/Pb were doped into commercial glasses by the melt-quenching method to substantially increase their refractive index. The refractive index of the commercial Ge28Sb12Se60 glass was increased from 2.6 to 3.05 by external doping with 20 atomic percentage (at%) of Ag. And the refractive index of commercially available Ge33As12Se55 glass was increased from 2.45 to 2.88 by external doping with 9 at% of Pb. These improvements effectively reduce the thickness of commercial lenses at the same radius of curvature and focal length. The physical and optical properties of commercial glasses doped with Ag/Pb in different proportions were systematically characterized.
Polarization singularities in planar electromagnetic resonators with rotation and mirror symmetries
Authors: Yang Jie , Zheng Xuezhi , Wang Jiafu , Zhang Anxue , Cui Tie Jun , Vandenbosch Guy A. E.
Published: March 2023

In this work, we apply the group representation theory to systematically study polarization singularities in the in-plane components of the electric fields supported by a planar electromagnetic (EM) resonator with generic rotation and reflection symmetries. We reveal the intrinsic connections between the symmetries and the topological features, i.e., the spatial configuration of the in-plane fields and the associated polarization singularities. The connections are substantiated by a simple relation that links the topological charges of the singularities and the symmetries of the resonator. To verify, a microwave planar resonator with the D8 group symmetries is designed and numerically simulated, which demonstrates the theoretical findings well. Our discussions can be applied to generic EM resonators working in a wide EM spectrum, such as circular antenna arrays, microring resonators, and photonic quasi-crystals, and provide a unique symmetry perspective on many effects in singular optics and topological photonics.
CustOmics: A versatile deep-learning based strategy for multi-omics integration
Authors: Benkirane Hakim , Pradat Yoann , Michiels Stefan , Cournède Paul-Henry
Published: March 2023

The availability of patient cohorts with several types of omics data opens new perspectives for exploring the disease’s underlying biological processes and developing predictive models. It also comes with new challenges in computational biology in terms of integrating high-dimensional and heterogeneous data in a fashion that captures the interrelationships between multiple genes and their functions. Deep learning methods offer promising perspectives for integrating multi-omics data. In this paper, we review the existing integration strategies based on autoencoders and propose a new customizable one whose principle relies on a two-phase approach. In the first phase, we adapt the training to each data source independently before learning cross-modality interactions in the second phase. By taking into account each source’s singularity, we show that this approach succeeds at taking advantage of all the sources more efficiently than other strategies. Moreover, by adapting our architecture to the computation of Shapley additive explanations, our model can provide interpretable results in a multi-source setting. Using multiple omics sources from different TCGA cohorts, we demonstrate the performance of the proposed method for cancer on test cases for several tasks, such as the classification of tumor types and breast cancer subtypes, as well as survival outcome prediction. We show through our experiments the great performances of our architecture on seven different datasets with various sizes and provide some interpretations of the results obtained. Our code is available on (https://github.com/HakimBenkirane/CustOmics).