bluuebunny/crossref_metadata_2025 huggingface dataset:
Local translatome sustains synaptic function in impaired Wallerian degeneration
Authors: Paglione Maria , Restivo Leonardo , Zakhia Sarah , Llobet Rosell Arnau , Terenzio Marco , Neukomm Lukas J
Published: October 2024

After injury, severed axons separated from their somas activate programmed axon degeneration, a conserved pathway to initiate their degeneration within a day. Conversely, severed projections deficient in programmed axon degeneration remain morphologically preserved with functional synapses for weeks to months after axotomy. How this synaptic function is sustained remains currently unknown. Here, we show that dNmnat overexpression attenuates programmed axon degeneration in distinct neuronal populations. Severed projections remain morphologically preserved for weeks. When evoked, they elicit a postsynaptic behavior, a readout for preserved synaptic function. We used ribosomal pulldown to isolate the translatome from these projections 1 week after axotomy. Translatome candidates of enriched biological classes identified by transcriptional profiling are validated in a screen using a novel automated system to detect evoked antennal grooming as a proxy for preserved synaptic function. RNAi-mediated knockdown reveals that transcripts of the mTORC1 pathway, a mediator of protein synthesis, and of candidate genes involved in protein ubiquitination and Ca2+ homeostasis are required for preserved synaptic function. Our translatome dataset also uncovers several uncharacterized Drosophila genes associated with human disease. It may offer insights into novel avenues for therapeutic treatments.
GelMA/tannic acid hydrogel decorated polypropylene mesh facilitating regeneration of abdominal wall defects
Authors: Huang Haonan , Tang Fuxin , Gan Wenchang , Li Ruibing , Hou Zehui , Zhou Taicheng , Ma Ning
Published: October 2024

Polypropylene (PP) mesh is a widely used prosthetic material in hernia repair due to its excellent mechanical properties and appropriate biocompatibility.
Optimizing alkaline and enzymatic extraction of black bean proteins: a comparative study of kinetics, functionality, and nutritional properties
Authors: Yang Jasmin S. , Dias Fernanda F. G. , de Moura Bell Juliana M. L. N.
Published: October 2024

This work explores the aqueous and enzyme-assisted extraction of black bean proteins with a focus on extraction yields, kinetics, protein functionality, and in vitro protein digestibility.
Active transfection of genetic materials using cyclodextrin-anchored nanovectors
Authors: Revdekar Amey , Salvi Bhagyashree V. , Shende Pravin
Published: October 2024

Incorporation of cyclodextrins in non-viral vector systems overcomes the delivery limitations of gene-based actives and offers multiple advantages for effective and safe therapeutic activity.
Medicinal chemistry-based perspectives on thiophene and its derivatives: exploring structural insights to discover plausible druggable leads
Authors: Thakur Shikha , Kumar Devendra , Jaiswal Shivani , Goel Kapil Kumar , Rawat Pramod , Srivastava Vivek , Dhiman Sonia , Jadhav Hemant R. , Dwivedi Ashish Ranjan
Published: October 2024

Thiophene is a privileged pharmacophore in medicinal chemistry owing to its diversified biological attributes.
Elucidating the interplay between entropy-driven and patch-mediated bonding in directing nanoscale assemblies
Authors: Akkunuri Kireeti , Zhang Xiangyu , Vo Thi
Published: October 2024

The interplay between directional patchy attraction and shape-driven entropic forces sculpts the spatial and orientational orderings between anisotropic building blocks, giving rise to symmetry breaking of pre-programmed interactions between particles.
Autonomous self-healing and superior tough polyurethane elastomers enabled by strong and highly dynamic hard domains
Authors: Jiang Hao , Yan Tong , Cheng Meng , Zhao Zhihao , He Tinglei , Wang Zhikun , Li Chunling , Sun Shuangqing , Hu Songqing
Published: October 2024

Hard domains composed of dense hydrogen bonds and π–π interactions endow elastomers with autonomous self-healing and excellent mechanical robustness.
Modulating Mn-doped NiO nanoparticles: structural, optical, and electrical property tailoring for enhanced hole transport layers
Authors: Islam Robiul , Abdur Rahim , Alam Md. Ashraful , Munna Nadim , Ahmed Aninda Nafis , Hossain Mosharof , Bashar Mohammad Shahriar , Islam Dipa , Jamal Mohammad Shah
Published: October 2024

Mn-doped NiO NPs, synthessized by chemical precipitation, showed reduced size and increased bandgap with higher doping, maintaining FCC structure even up to 8 wt%.
An investigation of the effect of the protein corona on the cellular uptake of nanoliposomes under flow conditions using quartz crystal microgravimetry with dissipation
Authors: Van der Sanden Nicholas , Paun Radu A. , Yitayew Michael Y. , Boyadjian Oscar , Tabrizian Maryam
Published: October 2024

The investigation of the effect of the protein corona on the cellular uptake of nanoliposome formulations in real-time under flow conditions by quartz crystal microbalance with dissipation as a biomimetic in vitro technique.
β-Cyclodextrin/Zn–Fe layered double hydroxides/graphitic carbon nitride nanomaterials based potentiometric sensor for paroxetine determination in environmental water samples
Authors: Ashry Ahmed , Rabia Mohamed , Mostafa Sahar Mahmoud , Korany Mohamed Ali , Farghali Ahmed Ali , Khalil Mohamed Magdy
Published: October 2024

Developing targeted and sensitive analytical techniques for drug monitoring in different specimens are of utmost importance.
Enhanced photocatalytic hydrogen production via water splitting using cobalt-based organic nanofibers under visible light irradiation
Authors: Barakat Nasser A. M. , Tayeb Aghareed M. , Hamad Rahma , Hashem Mohamed , Fouad Hassan , Kim Hak Yong , Hefny Rasha A.
Published: October 2024

Organic cobalt nanofibers were developed as efficient photocatalysts for hydrogen production via water splitting under visible light. The nanofibers exhibit enhanced photocatalytic performance and stability with methanol as a scavenger.
Carbon dot embedded CoNi bimetallic phosphide nanorods as an efficient electrocatalyst for overall water splitting
Authors: Long Yantong , Zhao Guoliang , Yang Liuxin , Xu Yongjun , Xu Chen
Published: October 2024

A 1D/3D structured bifunctional catalyst with CDs embedded into CoNi bimetallic phosphides exhibits outstanding water splitting performance in alkaline solution.
Defective phase engineering of S-scheme TiO2–SnS/SnS2 core–shell photocatalytic nanofibers for elevated visible light responsive H2 generation and nitrogen fixation
Authors: Ranjith Kugalur Shanmugam , Maleki Raza , Ghoreishian Seyed Majid , Mohammadi Ali , Rama Raju Ganji Seeta , Huh Yun Suk , Han Young-Kyu
Published: October 2024

To promote the fast separation of photogenerated charge carriers and promote stability, we designed core–shell TiO2–SnS/SnS2 heterostructures with enriched oxygen-related defect states without compromising their morphology.
Development of enzymatically crosslinked natural deep eutectogels: versatile gels for enhanced drug delivery
Authors: Meneses Liane , Bagaki Dimitra Antonia , Roda Ana , Paiva Alexandre , Duarte Ana Rita C.
Published: October 2024

We propose a new injectable eutectogel prepared by enzymatic crosslinking, using NADES, betaine : glycerol (2 : 1), as solvent. The potential of using this material with improved rheological properties as drug delivery system, has also been evaluated.
Double layer capacitance as a sensitive metric to monitor the formation of solid electrolyte interphases in Li–ion batteries
Authors: Schalenbach Maximilian , Wu Baolin , Tsai Chih-Long , Windmüller Anna , Raijmakers Luc , Yu Shicheng , Tempel Hermann , Eichel Rüdiger-A.
Published: October 2024

Step-protocol to measure the SEI formation by double layer capacitances with detangled time and potential contributions.
Advances in silicon photonics with quantum dot lasers
Authors: Arakawa Yasuhiko
Published: October 2024

More than forty years ago, in 1982, we proposed the concept of quantum dot lasers and at the same time theoretically predicted the temperature insensitivity of the threshold current. With advances in growth technology, the predicted characteristics were demonstrated in 2004, and high-temperature operation up to 220°C became possible in 2011. Currently, quantum dot lasers are positioned as a promising light source for silicon photonics, especially in terms of their ability to operate at high temperatures in co-packaged optical technology. In this talk, I will describe the historical development of quantum dot lasers and their integration into 5 mm square silicon-based transceiver chips, as well as the direct epitaxial growth of quantum lasers on silicon. The talk will also demonstrate the integration of quantum dot-based light sources, including single-photon sources, on silicon integrated circuits using transfer printing methods.
Plasmonic optoelectronic devices and metasurfaces
Authors: Berini Pierre
Published: October 2024

We report recent progress on optoelectronic devices and metasurfaces involving surface plasmons, enabled by metal-oxide-semiconductor (MOS) structures on Si and on epsilon-near-zero materials. We discuss electrically tuneable metasurfaces, high-speed electro-absorption modulators, and reflection modulators. Hot carriers created by the absorption of plasmons in metallic nanostructures on MOS structures are also discussed as they lead to novel device physics that open the door to new device concepts.
Machine learning-based evaluation of performance of silicon nitride waveguide fabrication: Gradient-boosted forests for predicting propagation and bend excess losses
Authors: Hinum-Wagner Jakob Wilhelm , Hoermann Samuel Marko , Feigl Gandolf , Schmidt Christoph , Kraft Jochen , Bergmann Alexander
Published: October 2024

The propagation and bend excess loss characteristics of silicon nitride strip waveguides at an 850 nm wavelength were explored in this study. The aim was to optimize fabrication processes using machine learning, particularly gradient-boosted forests, to achieve low-loss photonic integrated circuits (PICs) and accurately predict the losses. The impact of waveguide geometry and layer properties on loss was examined using a full factorial design of experiment. These machine learning models’ predictive accuracy and ability to capture complex relationships between fabrication parameters and different loss mechanisms were assessed. Key parameters and interactions were identified, improving PIC efficiency for photonic sensing applications.
Novel high contrast grating hollow core waveguides for enhanced gas spectroscopy
Authors: Thottoli Ajmal , Devarapu Ganga Chinna Rao , D’Orazio Antonella , Magno Giovanni , O’Faolain Liam
Published: October 2024

The article presents an innovative approach to confining waves in planar high contrast grating hollow core waveguides, design achieves a surface that reflects waves effectively while maintaining a structure that allows for high transmission. The unique side-open waveguide system also allows for gas flow through the sidewalls, making it suitable for gas spectroscopic techniques. The HCW design is specifically tailored for methane gas sensing at a wavelength of 3.27 μm. Numerical analysis shows that the transmittance can reach up to -0.41 dB. These findings demonstrate the potential of high-transmitting hollow-core waveguides for gas sensing, highlighting the effectiveness and cost-efficiency of chip-scale photonic integration.
Single Mode rib waveguide design using Machine Learning techniques
Authors: Mammeri Mohamed , Hashemi Babak , Crisci Teresa , Vergari Stefano , Gradassi Fabrizio , Casalino Maurizio , Della Corte Francesco Giuseppe
Published: October 2024

This work aim to determine a Single Mode (SM) Silicon-On-Insulator (SOI) rib waveguide using Machine learning (ML) techniques, which learn automatically by matching the input data with the target property. Random Forest (RF) is the ML algorithm used in this work. The accuracy of the model reaches 99% by using R2 score. The device is a rib waveguide based on Silicon (Si), with a cladding made of Silica (SiO2). The results obtained illustrate the conditions for SM, with the width and the rib etch-depth found to be relatively smaller compared to the total thickness. The ML approach have proven to be quick and effective regarding this problem.
Comparison measurements for hybrid evaluation approaches in optical nanometrology
Authors: Käseberg Tim , Bodermann Bernd , Sturm Matthias , Wurm Matthias , Siefke Thomas , Siaudinyté Lauryna , Tranum Rømer Astrid , Hansen Poul-Erik
Published: October 2024

In the pursuit of closing the gap between nanometrology and nanofabrication, we investigate the use of advanced optical far field methods for sub-wavelength parameter reconstruction. With the goal of establishing a hybrid evaluation scheme connecting different methods and including different information channels, we performed comparison measurements on a silicon line grating sample with buried as well as not buried surface relief lines. To this end, the results of our measurement are in good agreements with each other, and the collected structure data is feasible to be used for hybrid evaluation.
Correction of phase drifts in two-wavelength digital holographic microscopy using secondary reference waves
Authors: Šarbort Martin , Čížek Martin , Pavelka Jan , Lazar Josef
Published: October 2024

We present a two-wavelength digital holographic microscopy setup for surface topography measurement with single-point illumination and a method for correction of unwanted phase drifts using secondary reference waves.
Exploring the Frontiers of Non-Destructive Techniques: Shearography, Ultrasound Laser and Thermography
Authors: Graziano Fabiana , Coppola Sara , Vespini Veronica , Grilli Simonetta , Rippa Massimo , Ferraro Pietro
Published: October 2024

Non-destructive testing (NDT) techniques serve as indispensable tools across diverse industries, facilitating material and component inspection without inflicting damage. This article underscores the paramount importance of NDT methods in enhancing product quality, safety, and cost-effectiveness. Leveraging advanced techniques such as shearography, ultrasonic laser, and thermography, manufacturers can proactively identify defects during the production process, thereby reducing scrap and rework costs while enhancing overall product integrity. Shearography excels in surface defect detection, while ultrasonic laser offers sensitivity without necessitating direct contact, and thermography enables versatile temperature-based inspection. The synergistic coexistence of these techniques within NDT protocols maximizes inspection efficacy, ensuring high-quality and safe outcomes across various industries. By embracing a comprehensive approach to NDT, industries can optimize operational efficiency, minimize risks, and uphold stringent quality standards. In conclusion, the integration of shearography, ultrasonic laser, and thermography in NDT practices represents a cornerstone in maximizing inspection effectiveness and maintaining superior quality end safety standards across industrial sectors.
Influence of line edge roughness in optical critical dimension metrology
Authors: Siefke Thomas
Published: October 2024

We present the impact of line edge roughness (LER) on the optical critical dimension (OCD) metrology of nanostructures. The consideration of LER in OCD requires numerically expensive forward models and is therefore usually neglected. We present an analytical approach that allows estimation of the impact on the uncertainty. Systematic differences between CD measured by SEM and OCD were observed in different experiments. While SEM is basically sensitive to the local volume density, optical methods are sensitive to the permittivity of the material. We discuss an analytical upper bound on the contribution of the LER. For high index gratings, the contribution is as high as 3.7 nm for TM-polarized light and 1.2 nm for TE-polarized light, making this crucial for sub-nanometer metrology.
Microsphere-assistance in microscopic and confocal imaging
Authors: Hüser Lucie , Hagemeier Sebastian , Pahl Tobias , Lehmann Peter
Published: October 2024

Topographical as well as microscopic imaging of nanoscale surfaces plays a pivotal role across various disciplines. Nevertheless, achieving fast, label-free, and accurate characterization of laterally expanded structures below the diffraction limit remains challenging. Recent studies highlight the use of microsphere assistance for resolution improvement. Confocal microscopy, augmented by microspheres, enables the imaging of small structures that were previously inaccessible. This is experimentally compared with microsphere-assisted microscopy (MAM) to underline the decisive role of the confocal effect.
Modeling microcylinder-assisted conventional, interference and confocal microscopy
Authors: Pahl Tobias , Hüser Lucie , Eckhardt Tim , Hagemeier Sebastian , Rosenthal Felix , Diehl Michael , Lehmann Peter
Published: October 2024

We present how to develop virtual microcylinder- or microsphere-assisted surface topography measurement instruments. As the most critical part, the interaction between light, microcylinder and measurement object is considered based on the finite element method (FEM). Results are obtained for microcylinder-assisted conventional, interference, and confocal microscopes without necessity to repeat the time-consuming FEM simulations for each sensor.
Modeling of dimensions and sensing properties of gold gratings by spectroscopic ellipsometry and finite element method
Authors: Mukherjee Deshabrato , Burger Sven , Siefke Thomas , Gour Jeetendra , Bodermann Bernd , Petrik Peter
Published: October 2024

Gold gratings were measured by spectroscopic ellipsometry and modeled by the finite element method to investigate the capabilities of optical dimensional metrology for plasmonic diffractive structures. The gratings were prepared by electron beam lithography using parameters determined by finite element simulations for significant variations of the amplitude ratio and phase shift of the polarized reflection coefficients to achieve high sensitivity for both the measurement of the grating dimensions and the sensing capabilities. Sub-nanometer sensitivity was shown to determine the grating dimensions and the thickness of an adsorbed layer to be detected in both traditional reflection and Kretschmann-Raether (KR) configurations. The sensitivity for the refractive index of the ambient was calculated to be 10−5 at best, which is not significantly better than the sensitivities for plane gold layers in KR configurations. However, in diffraction-based resonant setups, the high sensitivity dips can be shifted to a larger spectral range, which is highly significant in many applications. It was also revealed that 2D models assuming a perfect geometry fit the measured ellipsometry spectra only qualitatively, leaving room for model development in the future.
Additive manufactured cerium oxide foils, used as pads for polishing processes of brittle-hard materials
Authors: Schulze Christian , Henkel Sebastian , Schultheiß Denise , Pipiorka Dominique , Bliedtner Jens , Kerber Albert , Rädlein Edda
Published: October 2024

A new concept for polishing pads for flat and spherical surfaces is introduced which comprises additive manufactured polishing pads made of cerium oxide. By using additive manufacturing technologies, polishing processes with polishing slurry can be substituted with tools containing bonded grain. The bonded polishing pads can be fabricated using rolling processes. The pad geometries can be adjusted by using laser cutting. Furthermore, surface modifications of the pad can be applied with laser processes to favour quality and economic factors of the polishing procedure. First results from the experimental setup are showing, that lapped surfaces with a roughness Rq of ~ 500 nm can be improved to approx. Rq = 30 nm roughness by polishing with bonded grain cerium oxide foils. Further approaches for future investigations and applications are proposed.
Desensitized telescope optical design: NSOS-α case study
Authors: Spanò Paolo , Tomelleri Raffaele , Roldán Narvión Manuel , Urrutia Sagasti Ander , Ayala Valencia Mario
Published: October 2024

NSOS-α is a 1.5-m aperture, F/1.55, wide field prime focus telescope for the Korea Astronomy & Space Science Institute (KASI) to discover and catalogue near-Earth asteroids, especially Potentially Hazardous Asteroids. Among the different optical designs, the current baseline is based onto a design with reduced sensitivities to both manufacturing and alignment tolerances, to optimize as-built performances instead of reducing nominal aberrations only. Different optimization techniques have been used and compared. As result, a fast and effective optimization procedure has been identified and implemented, and it will be used also during the manufacturing process to improve overall performance.
Differential ray tracing for an efficient computation of the Jacobian in the damped least-squares algorithm
Authors: Seger Tobias , Menke Christoph , Sonntag Matthias , Urban Karsten
Published: October 2024

We present a framework for the optimization of optical systems based up on the damped least-squares method and differential ray tracing. First, a mathematical description for the differentiation of the ray-surface intersection is introduced. It is observed that the structure of the optimization variables and operands can be exploited such that the Jacobian for the damped least-squares algorithm can be computed in the same computational complexity as the primal ray tracing for both forward and reverse mode algorithmic differentiation. To demonstrate the advantages of the method a freeform mirror system is analyzed.
Enhanced imaging of Subsurface Damage in optical glass SF6 with Optical Coherence Tomography using KOH wet etching
Authors: Frank Samson , Zhang Wei , Thelemann Dennis , Elies Oliver , Arnold Thomas , Bliedtner Jens
Published: October 2024

Mechanical cracks induced during grinding of brittle materials known as subsurface damage (SSD) reduce mechanical and optical properties of optical components. A characterisation of SSD is needed to guarantee a good quality and to optimize individual processes and processing chains. Current research focuses on non-destructive methods such as optical coherence tomography (OCT) to evaluate SSD depth and distribution and to replace currently established, but time-consuming and labour-intensive destructive methods. Yet the imaging of SSD remains challenging, even with high-resolution OCT providing a high sensitivity. The presented work proposes a combined measurement approach of enhanced SSD imaging by using a potassium hydroxide (KOH) wet etching process prior to OCT measurement. An etching process using 30% KOH at 80°C is applied and resulting etching rates are analysed. It is shown by an iterative etching experiment on optical glass SF6 that the KOH etching process enhances OCT signals of SSD under the surface, revealing up to 2.4-times deeper maximum SSD depths using an identical measurement setup.
Laser-based fabrication chain enabling high quality mini aspheres
Authors: Lämmler Sven , Bischof David , Walder Simon , Fähnle Oliver
Published: October 2024

In recent years, 3D machining in glass for micro-components has seen a notable boost, notably with the development of a novel optical fabrication chain. This approach uses lasers for shaping and polishing, enabling the creation of complex mini-optics efficiently. The process begins with selective laser-induced etching (SLE) to define the optics’ outer shape and surface figure. Subsequent polishing, using a “one-shot laser polishing” technique, removes imperfections and reduces roughness in a single step, achieving optical-grade smoothness. This fabrication chain is applicable to mini-aspheres as well, enhancing their production efficiency. Additionally, it allows for wafer-level production, where multiple mini-optics are interconnected on a single glass substrate.
Optical component reliability in high-energy laser systems: Challenges and insights
Authors: Mureșan Mihai-George , Novák František , Uvarova Liliia , Vanda Jan , Brajer Jan , Mocek Tomáš
Published: October 2024

The laser-induced damage resistance of large optical components remains an important limitation for the maintenance costs, reliability, and further development of high energy/high-power (HEL/HPL) laser systems. With numerous manufacturers providing different laser-induced damage threshold (LIDT) values in the nanosecond regime, a simple ranking based on numbers alone may not provide a clear picture of the best choice. Variations in testing procedures, albeit following the ISO 21254 standard, further complicate the selection process. By employing a comprehensive 1-on-1 test procedure, it becomes possible to observe various parameters that influence LIDT values. An overview on how the laser beam size, the spectral characteristics of the tested optic and possible contamination of the surface are influencing the LIDT values will be presented.
Polishing performance of 3D-printed multi-material photopolymer tools on glass
Authors: Kern Kerstin , Schultheiss Denise , Allaart Jan , Schulze Christian , Henkel Sebastian , Faehnle Oliver , Bode Jürgen , Surberg Cord Henrik , Bliedtner Jens
Published: October 2024

Due to the increasing demands and complexity of optical glass components to be processed in the future, advanced technologies and precision machining methods will be required in order to produce high-quality optics economically. The polyjet process enables the production of 3D printed gradient index (GRIN) polishing tools with hardness gradients by combining different polymer materials for e.g. synchrospeed polishing. In terms of their geometric design, these tools are significantly more flexible than conventional ones, where the polishing cloth must be glued to metal tool holders. The composition of the polishing pad material directly influences the process efficiency and quality at which the glass is polished. In a laboratory test the influence of the mechanical properties of the multi-material pads on process efficiency, i.e. their long-term stability and the polishing rate of the glass workpiece is demonstrated.
Simultaneous atmospheric pressure plasma jet etching and laser irradiation for ultra-precise optical glass processing
Authors: Heinke Robert , Arnold Thomas , Ehrhardt Martin , Lorenz Pierre , Zimmer Klaus
Published: October 2024

The use of beam-based technologies to process optical elements with nanoscale precision enables the fabrication of freeform surfaces. In particular, atmospheric pressure plasma jets (APPJs) have desirable properties, e.g., depth precision < 5 nm, low surface roughness and processing at atmospheric conditions. However, the composition of optical glasses and glass ceramics, containing metal oxides, leads to the formation of non-volatile reaction products that remain on the substrate surface. These residues reduce the etching rate and cause severe roughening of the surface. Laser irradiation has already been demonstrated as a promising option for removing the residual layer and the aim of the current work is to integrate it into the APPJ system for simultaneous processing. Therefore, an excimer laser (λ = 248 nm; tPulse = 20 ns) with a maximum pulse frequency of 100 Hz was added to a plasma jet setup and experiments with varying laser fluences as well as laser frequencies were performed on N-BK7 substrates. White light interferometry was used to analyse the samples. The experiments showed an improved etching result with higher removal rates for the combined process at high laser pulse frequency (100 Hz) and fluences in the range of 0.1-0.45 J·cm-2.
Twyman effect in laser polishing of fused silica wafers
Authors: Lämmler Sven , Bischof David , Fähnle Oliver
Published: October 2024

This paper investigates the challenges of minimizing wafer deformation during laser polishing of fused silica. The focus is on the Twyman effect, which causes unwanted curvature in thin plates. Strategies to reduce stress-induced deformation are proposed to enhance the reproducibility of the laser polishing process.
A microfluidic scanning flow cytometer with superior signal-to-noise-ratio for label-free characterization of small particles
Authors: Reale Riccardo , Ghoreishi Maryamsadat , Peruzzi Giovanna , Ruocco Giancarlo , Leonetti Marco
Published: October 2024

Single-cell analysis without immune-specific labelling is essential across research fields, but conventional flow cytometers (FCMs) struggle with label-free analysis. We introduce a novel microfluidic scanning flow cytometer (μSFC) designed for label-free analysis within a simple microfluidic chip. Our system outperforms traditional FCMs for label-free analysis but its signal-to-noise ratio (SNR) limits the minimum detectable size. We present three modifications to enhance SNR and improve the smallest detectable particle size: additional neutral optical density filtering, a lower noise-equivalent-power photoreceiver, and laser spot size reduction. These improvements enable reliable characterization of particles as small as 3 μm. Experimental results validate the correlation between angular profile oscillations and particle size. While reliable detection down to 1 μm is achieved, further refinement is needed. The simplicity and low setup of the μSFC make it promising for integration into multi-parametric single-cell analysis systems, facilitating comprehensive cellular characterization for diagnostic and point-of-care applications.
Advancing Optical Coherence Tomography through Opto-Electronic Frequency Shifting
Authors: Urban Dorian R. , Novak Pavel , Preciado Miguel , Vettenburg Tom
Published: October 2024

Optical Coherence Tomography (OCT) stands out for its ability to combine the high resolution of microscopy with the penetration-depth of clinical imaging. However, in practice this is still limited to a few millimetres. Interestingly, the imaging-depth of the latest swept-source systems is not limited by their spectral width but by the analog-to-digital sampling rate. In lieu of slow reference arm length adjustments, we leverage opto-electronic frequency shifting. This allows for depth adjustments on the microsecond timescale and a modest detector bandwidth of 200MHz. The opto-electronic scheme immediately gives us access to an 8mm range, a fourfold increase over the nominal 2mm range of the source. Moreover, by circumventing the need for a mechanical reference arm, changes in the axial displacement of the sample can be compensated in real-time. This makes it attractive for imaging arbitrarily-curved surfaces. We showcase this with wide-field OCT imaging of the curved retina.
Gold nanoparticles and near-infrared light as a new tool to enhance tissue regeneration
Authors: Dell’Aversano Natalia , Amenta Maria Laura , Rippa Massimo , Moros Maria , Tino Angela , Tortiglione Claudia , Marchesano Valentina
Published: October 2024

Controlled temperature elevation within biological tissues, known as hyperthermia, holds promise as a therapeutic treatment. Its efficacy depends on several factors including timing, pulsing, and repetition. Recent research indicates the potential of heat-based therapies not only for cancer treatment but also in tissue regeneration. The usage of photothermal agents, such as gold nanoparticles, enables precise spatio-temporal heat generation, known as photothermal therapy (PTT). Hydra vulgaris, with their unique regenerative capabilities, serve as valuable models for exploring the effects of nanoparticles on tissue regeneration. AuNPs thanks to their plasmonic properties can induce physiological responses in the animals under near-infrared (NIR) irradiation, ranging from cell ablation to programmed cell death or thermotolerance. By tuning the NIR irradiation and the AuNPs dose, the capability of treated polyps to regenerate the missing heads under photostimulation will be dissected, at whole animal, cellular and molecular levels and compared to exposure to external macroscopic heat sources.
Highly sensitive detection of a neurodegenerative protein biomarker by using the pyro-electrohydrodynamic jet
Authors: Di Natale Concetta , Coppola Sara , Vespini Veronica , Tkachenko Volodymyr , Russo Simone , Carbone Stefania , Luciani Giuseppina , Vitiello Giuseppe , Ferranti Francesca , Mari Silvia , Ferraro Pietro , Maffettone Pier Luca , Grilli Simonetta
Published: October 2024

A set of protein biomarkers are largely recognized as responsible of neurodegeneration mechanisms and hence as potential targets to be detected in low abundant concentrations in body fluids for performing early diagnosis. As an example, the Tau protein experiences a transition phase from a native disorder conformation into a preaggregation state, which leads to fibrillization processes. Here we show the possibility to detect Tau in urine samples at sub-picogram level, through the concentration effect of the pyro-electrohydrodynamic (p-jet) technique. An immunofluorescence protocol is applied to concentrated p-jet spots able to reduce drastically the diffusion effects in the antibody-antigen reaction. A set of diluted samples were prepared, and the fluorescence signal was detected by a confocal scanner. We achieved an excellent linear response with a significant signal-to-noise ratio down to 0.25 pg/mL. In perspective, the technique could be integrated into a compact device to be used for monitoring the early stage associated to neurodegenerative syndromes in different scenarios such as for example in long-term human space exploration missions.
Implantable Micro-optics for label-free non-linear imaging
Authors: Marini Mario , Panzeri Davide , Nardini Alessandra , Kariman Behjat S. , Conci Claudio , Sironi Laura , Inverso Donato , Jacchetti Emanuela , Martinez Vázquez Rebeca , Osellame Roberto , Collini Maddalena , Cerullo Giulio , Raimondi Manuela Teresa , Kabouraki Elmina , Farsari Maria , Kehaghias Nikos , Tourlouki Konstantina , Chirico Giuseppe
Published: October 2024

Non-linear excitation microscopy offers superior in-vivo imaging but faces challenges in deep tissue. High numerical aperture beams suffer spherical aberrations, while tissue scattering impacts image quality. To address this, we propose implantable microlenses for precise focusing below the skin in lab animals. By using low numerical aperture lasers, we avoid spherical aberrations induced by high NA objectives. Our study presents various microlens designs differing in size, shape, and fabrication methods, all on glass or organo-hybrid ceramic substrates. This approach shows promise for enhancing deep tissue imaging, facilitating better understanding of biological processes in vivo.
Optofluidic flow cytometer with in-plane spherical mirror for signals enhancement
Authors: Zorzi Filippo , Bonfadini Silvio , Aloisio Ludovico , Moschetta Matteo , Storti Filippo , Simoni Francesco , Lanzani Guglielmo , Criante Luigino
Published: October 2024

Statistical analysis of properties of single microparticles, such as cells, bacteria or plastic slivers, has attracted increasing interest in recent years. In this field flow cytometry is considered the gold standard technique, but commercially available instruments are bulky, expensive, and not suitable for use in Point-of-Care (PoC) testing. Microfluidic flow cytometers, on the other hand, are small, cheap and can be used for on-site analysis. However, in order to detect small particles, they require complex geometries and the aid of external optical components. To overcome these limitations here we present an opto-fluidic flow cytometer with an integrated 3D in-plane spherical mirror for enhanced optical signal collection. As result the signal-to-noise ratio is increased by a factor of 6, enabling the detection of particle sizes down to 1.5μm. The proposed optofluidic detection scheme allows the simultaneous collection of particles fluorescence and scattering - using a single optical fiber - which is crucial to easily distinguish particle populations with different optical properties. The devices have been fully characterized using fluorescent polystyrene beads of different sizes. As a proof of concept for potential real-world applications, signals from fluorescent HEK cells and Escherichia coli bacteria were analyzed.
Porous Silicon modified by Molecularly Imprinted Polymers for Interleukin-6 (IL-6) detection
Authors: Nocerino Valeria , Siciliano Giulia , Rea Ilaria , Dardano Principia , Chiriacò M. S. , Ferrara F. , Primiceri E. , De Stefano Luca
Published: October 2024

In this study, we present an innovative optical biosensor designed for the precise detection of Interleukin-6 (IL-6), a crucial cytokine associated with various pathological conditions. Our biosensor is based on silicon porous material meticulously modified with a molecularly imprinted polymer (MIP), ensuring specific and sensitive recognition of IL-6 molecules. Fabrication process involves the electrochemical etching of silicon porous chips followed by the electrodeposition of MIP, tailored to selectively bind IL-6 targets. Through rigorous testing across a range of IL-6 concentrations, our sensor exhibits remarkable sensitivity, showcasing discernible optical responses proportional to the varying analyte concentrations. Furthermore, we assessed the sensor's performance using bovine serum, a complex biological matrix, to simulate real-world sample conditions. Encouragingly, the sensor maintains its selectivity and optical response in the presence of serum components, affirming its robustness and applicability in practical diagnostic settings.
Terahertz Radiation for Demethylation of Cancer Cells
Authors: Son Joo-Hiuk
Published: October 2024

Carcinogenesis involves DNA methylation which is a primary alteration in DNA in the development of cancer before genetic mutation. Because the abnormal DNA methylation is found in most cancer cells, the assessment of DNA methylation using terahertz radiation can be a novel optical method to detect and control cancer. The methylation has been directly observed by terahertz time-domain spectroscopy and this epigenetic chemical change could be manipulated to the state of demethylation using resonant terahertz radiation. Demethylation of cancer cells is a key issue in epigenetic cancer therapy and our results demonstrate the feasibility of the cancer treatment using optical technique.
Brick-Based Silicon Optomechanical Cavity Sensor for Nanoparticles Mass Detection
Authors: Grau Alberto , Mercadé Laura , Ortiz Raúl , Martínez Alejandro
Published: October 2024

A novel design for an optomechanical cavity consisting of a series of rectangular silicon nanobricks, with each brick acting as an independent mechanical resonator but all coupled to a same optical field, is proposed, and numerically demonstrated. Each brick is placed on top of a thin silica pillar that provides mechanical support whilst isolates the individual mechanical resonances. The mass sensing capabilities of this cavity are studied through numerical simulations, proving that a point mass approximation can be used for silica nanoparticles with radius smaller than 100 nm, and that different nanoparticles can be measured independently but simultaneously.
Polarization mixing, bound states in a continuum, and exciton-polaritons in photonic crystal slabs by a guided-mode expansion approach
Authors: Zanotti Simone , Minkov Momchil , Nigro Davide , Gerace Dario , Fan Shanhui , Andreani Lucio Claudio
Published: October 2024

Photonic crystal (PhC) slabs, or patterned multilayer waveguides, are known to support truly guided modes with no losses, as well as quasi-guided modes that lie in the continuum of far-field radiation. In this contribution, we present a guided-mode expansion approach – and the corresponding free software named legume – that allows calculating a number of features of PhC slabs: (a) symmetry properties and the issue of polarization mixing in coupling to far-field radiation; (b) the occurence of bound states in a continuum, which have infinite Q-factor and give rise to topological singularities of the far-field polarization; (c) the description of active two-dimensional layers through a suitably formulated light-matter coupling Hamiltonian, allowing to describe the regime of strong coupling leading to photonic crystal polaritons. Comparison with rigorous coupled-wave analysis, and the insurgence of non-hermitian features in the optical properties, are also addressed.
Femtosecond laser written waveguides in Dy-doped Y3Al5O12 for yellow lasers
Authors: Demaimay Jonathan , Loiko Pavel , Gohier Ambre , Romero Carolina , Rodríguez Vázquez de Aldana Javier , Zhang Zhonghuan , Mateos Xavier , Xu Xiaodong , Camy Patrice , Braud Alain
Published: October 2024

Depressed cladding waveguides in a Dy:YAG crystal were fabricated by femtosecond direct laser writing. Their μ-luminescence characterization in the visible revealed well-preserved emission properties in the core region, a strong material modification within the damage tracks, and an anisotropic stress field associated with ear-like side structures. The developed waveguides are promising for yellow lasers.
Inhomogeneous spectral line broadening and site distribution in “mixed” Er:(Sc,Y)2O3 laser ceramics
Authors: Normani Simone , Loiko Pavel , Maksimov Roman , Shitov Vladislav , Osipov Vladimir , Braud Alain , Camy Patrice
Published: October 2024

Erbium-doped “mixed” yttria-scandia (ScxY1-x)2O3 transparent laser ceramics were fabricated by vacuum sintering at 1750 °C from laser-ablated nanoparticles. Their absorption and mid-infrared emission properties were studied. The addition of Sc3+ induces a strong inhomogeneous spectral line broadening, modifies the crystal field and affects the distribution of Er3+ ions over C2 and C3i symmetry sites. Due to their broadband emission properties, Er:(ScxY1-x)2O3 ceramics are appealing for 2.8-μm lasers.
80 W, up to 2 mJ Yb-based laser multi-pass-cell post-compression down to sub-20 fs: Experimental and numerical results
Authors: Hergott Jean-François , Réau Fabrice , Lericheux Nicolas , Guer Matthieu , Marroux Hugo , Géneaux Romain , Tcherbakoff Olivier , Lepetit Fabien , Bresteau David , Ruchon Thierry , Salières Pascal , Auguste Thierry , D’Oliveira Pascal
Published: October 2024

In the last years, different methods of laser pulse post-compression have proven their efficiency. Nonlinear spectral broadening achieved when coupling an ultrafast pulse in a gas-filled multi-pass-cell (MPC) provides common pulse compression factors of 10 to 20, depending on the initial pulse duration. We report here on the compression of up to 2 mJ, 330 fs pulses of an Ytterbium (Yb) based laser down to sub-20 fs (compression factor of 17), using argon-filled MPCs, at the limit of temporal pulse breakup. Numerical calculations reproducing the experiment data, and demonstrating the importance of the driver pulse profile on the shape of the broadened spectra, are discussed.
A UV-XUV attosecond beamline with few-femtosecond tunable ultraviolet pump pulses
Authors: Colaizzi Lorenzo , Mocci Daniele , Pini Marta , Kotsina Nikoleta , Nordmann Joleik , Brahms Chris , Travers John , Lucchini Matteo , Borrego-Varillas Rocío , Reduzzi Maurizio , Nisoli Mauro
Published: October 2024

Ultrafast charge transfer processes in organic materials which occur in organic materials are fundamental for advancing solar energy conversion technologies. Understanding these phenomena on a short time scale induced by visible and ultraviolet (UV) light is crucial for future control and engineering of these molecules. Here, we present a novel attosecond beamline featuring Resonant Dispersive Wave emission for generating sub-3 fs tunable pump pulses in the UV region and High Harmonic Generation (HHG) in a semi-infinite gas cell for isolated attosecond pulse generation in the Extreme ultraviolet range.
Experimental demonstration of a temporal pulse shaping method based on nonlinear chirp
Authors: Parize Gautier , Natile Michele , Guichard Florent , Comby Antoine , Hanna Marc , Georges Patrick
Published: October 2024

We present a general temporal shaping method based on spectral phase-only modulation for ultrafast laser sources. We explain the working principle of this technique and use it experimentally to generate a ramp-shaped pulse at the output of a laser source delivering 30 μJ 200 fs pulses at 500 kHz. This pulse is then launched inside a multipass cell to demonstrate non-linear wavelength shifting. A spectral tunability of 11 nm around the center wavelength of 1030 nm is achieved.
Sub-20-fs UV–XUV Beamline for Ultrafast Molecular Pump-Probe Spectroscopy
Authors: Severino Stefano , Mai Lorenzo , Crego Aurora , Medeghini Fabio , Vismarra Federico , Frassetto Fabio , Poletto Luca , Lucchini Matteo , Reduzzi Maurizio , Nisoli Mauro , Borrego-Varillas Rocío
Published: October 2024

The experimental investigation of chemically and biologically relevant dynamics induced by visible or ultraviolet (UV) light requires high temporal resolution and spectroscopic techniques capable of resolving the complexity of these processes. Time-resolved photoelectron spectroscopy has proven to be a key tool for the study of these dynamics, but most studies have been conducted with a limited temporal resolution of about 100 fs. Furthermore, typical schemes employ a deep-UV probe, which limits the observations window and leads to spectrally congested traces. In this work, we present a UV pump – extreme-UV probe beamline with sub-20 fs temporal resolution, unambiguously characterized by an in-situ photoelectron cross-correlation measurement. As an example of the capability of the setup, we show a time-resolved investigation of the non-adiabatic dynamics of acetylacetone. The extreme temporal resolution allows us to resolve the passage through the first conical intersection and to identify the coherently excited vibrational modes.
Approaching maximal precision of Hong-Ou-Mandel interferometry with non-perfect visibility
Authors: Meskine Othmane , Descamps Eloi , Keller Arne , Lemaître Aristide , Baboux Florent , Ducci Sara , Milman Pérola
Published: October 2024

This work explores precision limits in two-photon Hong-Ou-Mandel interferometry under non-perfect visibility. A theoretical model is developed and experimentally validated using different quantum states. A remarkable ratio of 0.97 between the experimental precision and the quantum limit is observed, establishing a new benchmark in the field.
Generating clean few-cycle pulses in an all-bulk multipass cell scheme
Authors: Segundo Staels Víctor Wilfried , Conejero Jarque Enrique , San Roman Julio
Published: October 2024

We theoretically demonstrate the generation of clean few-cycle pulses in a three-stage all-bulk multipass cell scheme. By meticulously selecting the number of round trips and the width of the material used in each cell, we are able to keep the three stages in the enhanced frequency chirp regime. The results show the generation of short and clean pulses, with compression factors approaching 50 with a final duration below 1.5 cycles.
Phase-Matched Second-Harmonic Generation from Metasurfaces Inside Multipass Cells
Authors: Mekhael Madona , Stolt Timo , Vesala Anna , Rekola Heikki , Hakala Tommi K. , Fickler Robert , Huttunen Mikko J.
Published: October 2024

We demonstrate a scalable approach to increase conversion efficiencies of nonlinear metasurfaces by incorporating them into multipass cells and allowing the pump beam to pass several times through the metasurfaces. As a proof of principle, we achieve phase matching of the second-harmonic generation (SHG) signal with superlinear dependence on the number of passes. We measure an order of magnitude enhancement in the SHG signal when the incident pump traverses the metasurface up to 9 passes. The generic nature of our approach holds promise for diverse applications in nonlinear optics.