Photonics

9 pages, 4292 KiB

Open AccessArticle

High-Quality-Factor Electromagnetically Induced Transparency in All-Dielectric Metasurfaces Supporting Quasi-Bound States in the Continuum

by Lei Zhang, Zeyang Chu and Suxia Xie

Photonics 2025, 12(3), 291; https://doi.org/10.3390/photonics12030291 - 20 Mar 2025

Viewed by 228

Abstract

Electromagnetically induced transparency based on bound states in the continuum (EIT-BIC) has emerged as a significant research focus in photonics due to its exceptionally high quality factor (Q-factor). This study investigates a periodic dielectric metasurface composed of silicon bar–square ring resonators, [...] Read more.

Electromagnetically induced transparency based on bound states in the continuum (EIT-BIC) has emerged as a significant research focus in photonics due to its exceptionally high quality factor (Q-factor). This study investigates a periodic dielectric metasurface composed of silicon bar–square ring resonators, with a comparative analysis of both monolayer and bilayer configurations. Through systematic examination of transmission spectra, electric field distributions, and Q-factors, we have identified the existence of EIT-BIC and quasi-BIC phenomena in these structures. The experimental results demonstrate distinct characteristics between monolayer and bilayer systems. In the monolayer configuration, a single BIC is observed in the low-frequency region, with its quasi-BIC state generating an EIT window. In contrast, the bilayer structure exhibits dual BICs and dual EIT phenomena in the same spectral range, demonstrating enhanced spectral modulation capabilities. Notably, in the high-frequency region, both configurations maintain a single BIC, with the number remaining independent of structural layer count. The number and spectral positions of BICs can be effectively modulated through variations in incident angle and structural symmetry. In particular, the bilayer configuration demonstrates superior modulation characteristics under oblique incidence conditions, where the quasi-BIC linewidth broadens with increasing incident angle, forming a broader high-Q transparency window. This comparative study between monolayer and bilayer systems not only elucidates the influence of structural layers on BIC characteristics but also provides new insights for flexible spectral control. These findings hold significant implications for artificial linear modulation and play a crucial role in the design of future ultra-high-sensitivity sensors, particularly in optimizing performance through structural layer engineering. Full article

(This article belongs to the Special Issue Terahertz Advancements in Fibers, Waveguides and Devices)

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21 pages, 2632 KiB

Open AccessReview

Recent Advances in Integrated Vibration Sensing and Communication in Digital Subcarrier Multiplexing Systems

by Bang Yang, Jianwei Tang, Linsheng Fan, Yaguang Hao, Chen Cheng, Shangyi Wang, Shuang Gao, Zhongliang Sun, Junpeng Liang, Weisheng Hu, Yanfu Yang and Jinlong Wei

Photonics 2025, 12(3), 290; https://doi.org/10.3390/photonics12030290 - 20 Mar 2025

Viewed by 229

Abstract

Digital subcarrier multiplexing (DSCM) systems offer flexibility and software configurability, making them promising for point-to-multipoint (P2MP) communications. Meanwhile, DSCM systems exhibit enhanced communication damage tolerance and capabilities for damage monitoring and compensation. These capabilities include tolerance to equalized enhanced phase noise (EEPN) and [...] Read more.

Digital subcarrier multiplexing (DSCM) systems offer flexibility and software configurability, making them promising for point-to-multipoint (P2MP) communications. Meanwhile, DSCM systems exhibit enhanced communication damage tolerance and capabilities for damage monitoring and compensation. These capabilities include tolerance to equalized enhanced phase noise (EEPN) and high-speed Polarization State (SOP) tracking. The subcarrier intervals in DSCM systems naturally allow the insertion of pilot or training sequences. This facilitates enhanced communication functionality and integrated sensing capabilities. This review article summarizes the principles and schemes of integrated communication and sensing in DSCM systems. It analyzes performance in communication enhancement and sensing integration. Finally, it discusses unresolved technical challenges and future technological prospects. Full article

(This article belongs to the Special Issue Photonics: 10th Anniversary)

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8 pages, 2426 KiB

Open AccessCommunication

Broadband On-Chip Directional Coupler with Oblique Nanoslits

by Can Chen, Qingfang Wang, Jinzhan Zhong, Xinrui Lei and Qiwen Zhan

Photonics 2025, 12(3), 289; https://doi.org/10.3390/photonics12030289 - 20 Mar 2025

Viewed by 203

Abstract

Directional coupling of light at the nanoscale plays a significant role in both fundamental research and practical applications, which are crucial for the development of on-chip photonic devices. In this work, we propose a broadband directional coupler for surface plasmon polaritons (SPPs) utilizing [...] Read more.

Directional coupling of light at the nanoscale plays a significant role in both fundamental research and practical applications, which are crucial for the development of on-chip photonic devices. In this work, we propose a broadband directional coupler for surface plasmon polaritons (SPPs) utilizing a pair of obliquely perforated nanoslits. We demonstrate that tilting the slits significantly enhances the sensitivity of plasmonic coupling phase variation to the wavelength of the incident light, enabling precise wavelength-dependent control over SPP propagation. By optimizing the width and tilting angle of each nanoslit, we achieve an extinction ratio exceeding 10 dB with a bandwidth exceeding 400 nm and a maximum unidirectional transmission of up to 30 dB. This broadband directional SPP coupler presents a promising platform for the design and fabrication of integrated plasmonic circuits and high-performance optical devices and sensors. Full article

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8 pages, 1952 KiB

Open AccessCommunication

Structured Optical Toroidal Vortices with Rotational Symmetry

by Jinzhan Zhong and Qiwen Zhan

Photonics 2025, 12(3), 288; https://doi.org/10.3390/photonics12030288 - 20 Mar 2025

Viewed by 235

Abstract

Toroidal vortices, as intriguing topological structures, play a fundamental role across a wide range of physical fields. In this study, we theoretically propose a family of structured optical toroidal vortices as generalized forms of toroidal vortices in paraxial continuous wave beams. These structured [...] Read more.

Toroidal vortices, as intriguing topological structures, play a fundamental role across a wide range of physical fields. In this study, we theoretically propose a family of structured optical toroidal vortices as generalized forms of toroidal vortices in paraxial continuous wave beams. These structured optical toroidal vortices exhibit unique rotational symmetry while preserving the topological properties of standard toroidal vortices. The three-dimensional topological structures demonstrate l-fold rotational symmetry, which is closely related to the topological charges. Structured toroidal vortices introduce additional topological invariants within the toroidal light field. These topological light fields hold significant potential applications in the synthesis of complex topological structure and optical information encoding. Full article

(This article belongs to the Special Issue Fundamentals and Applications of Vortex Beams)

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12 pages, 3236 KiB

Open AccessArticle

Simulation Study of Readily Manufactured High-Performance Polarization Gratings Based on Cured HSQ Materials

by Jiatong Liu, Jun Xu, Ruiting Hao, Gang Chen, Wen Wang, Pengcheng Sheng, Huizi Li and Yunzhi Wang

Photonics 2025, 12(3), 287; https://doi.org/10.3390/photonics12030287 - 20 Mar 2025

Viewed by 221

Abstract

Polarimetric imaging technology captures both traditional intensity information and multidimensional polarization data, significantly enhancing target–background contrast and boosting detection system recognition. However, monolithic integration of grating polarizers into large-area focal plane arrays faces challenges, including complex fabrication, low extinction ratios, and high rates [...] Read more.

Polarimetric imaging technology captures both traditional intensity information and multidimensional polarization data, significantly enhancing target–background contrast and boosting detection system recognition. However, monolithic integration of grating polarizers into large-area focal plane arrays faces challenges, including complex fabrication, low extinction ratios, and high rates of blind elements. In this article, we present a simulation model for the fabrication of high-performance polarized gratings using electron-beam cured HSQ (Hydrogen Silsesquioxane Polymer) materials technology. By optimizing structural design, a high transmittance of 88–97% and an extinction ratio of ≥55 dB over a wide spectral range of 3–5 µm was achieved. This result offers a new approach to advancing high-performance infrared polarization imaging technology. Full article

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14 pages, 9076 KiB

Open AccessArticle

Inverse Design of Wavelength-Selective Film Emitter for Solar Thermal Photovoltaic System

by Wenxiao Long, Yulian Li, Yuanlin Chen, Qiulong Chen and Dengmei Yu

Photonics 2025, 12(3), 286; https://doi.org/10.3390/photonics12030286 - 20 Mar 2025

Viewed by 229

Abstract

Solar photovoltaic (PV) technology is developing quickly due to the continual rise in demand for energy and environmental protection. Solar thermal photovoltaic (STPV) systems can break the Shockley–Queisser limit of conventional PV systems by reshaping the solar spectrum using selective absorbers and emitters. [...] Read more.

Solar photovoltaic (PV) technology is developing quickly due to the continual rise in demand for energy and environmental protection. Solar thermal photovoltaic (STPV) systems can break the Shockley–Queisser limit of conventional PV systems by reshaping the solar spectrum using selective absorbers and emitters. However, the traditional design method relies on the designer’s experience, which fails to achieve rapid designing of STPV devices and greatly improve the performance. In this paper, an STPV thin-film selective emitter is inversely designed based on a genetic algorithm. The optimized structure consists of SiO₂ and SiC layers alternately stacked on a Cr substrate, whose emissivity can reach 0.99 at 1.86 μm. When combined with an InGaAsSb cell, the power conversion efficiency can be up to 43.3% at 1673 K. This straightforward and easily scalable film emitter can be designed quickly and gain excellent efficiency, which promotes the practical application of STPV systems. Full article

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13 pages, 40037 KiB

Open AccessArticle

Interferometric Surface Analysis of a Phase-Only Spatial Light Modulator for Surface Deformation Compensation

by Rania M. Abdelazeem, Mostafa Agour and Salah Hassab Elnaby

Photonics 2025, 12(3), 285; https://doi.org/10.3390/photonics12030285 - 20 Mar 2025

Viewed by 219

Abstract

A spatial light modulator (SLM) is a key element in several applications, but it is subject to surface deformation due to manufacturing imperfections or environmental factors. Therefore, the current study aims to analyze and compensate for such deformations in a phase-only SLM using [...] Read more.

A spatial light modulator (SLM) is a key element in several applications, but it is subject to surface deformation due to manufacturing imperfections or environmental factors. Therefore, the current study aims to analyze and compensate for such deformations in a phase-only SLM using a Michelson interferometer. The recorded interferogram represents the interference between the wavefront reflected from the SLM surface (object wave) and a reference wave. Noise in the recorded interferogram can degrade the accuracy of phase measurements. Various digital filtering techniques were applied to improve the signal-to-noise ratio (SNR) of the interferogram. The filtered interferogram enabled accurate phase extraction through Fourier transform processing and side peak selection using a spatial carrier frequency method. Additionally, phase errors caused by the tilt of the reference beam were corrected. Thereafter, the conjugate of the corrected phase distribution was used to calculate a phase-only computer-generated hologram (CGH), which was displayed on the SLM to compensate for surface deformations. The effectiveness of the proposed compensation procedure was confirmed by a second phase measurement, which demonstrated improved SLM performance. This study highlights the impact of combining the interferometric techniques with digital processing for precise surface deformation analysis. Full article

(This article belongs to the Special Issue Emerging Trends in Spectral Analysis with Optical Sensors: Modern Approaches and Applications)

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11 pages, 2536 KiB

Open AccessArticle

Parts-per-Billion Detection of Hydrogen Sulfide via Cavity Ring-Down Spectroscopy

by Wei Xu, Xuejun Wang, Lei Zhao, Jun Zou and Bing Chen

Photonics 2025, 12(3), 284; https://doi.org/10.3390/photonics12030284 - 20 Mar 2025

Viewed by 258

Abstract

Rapid and precise detection of hydrogen sulfide (H₂S) at trace levels is critical for industrial safety and environmental air quality monitoring, yet existing methods often struggle with cost, speed, or sensitivity. A cost-effective cavity ring-down spectroscopy (CRDS) analyzer is presented, incorporating [...] Read more.

Rapid and precise detection of hydrogen sulfide (H₂S) at trace levels is critical for industrial safety and environmental air quality monitoring, yet existing methods often struggle with cost, speed, or sensitivity. A cost-effective cavity ring-down spectroscopy (CRDS) analyzer is presented, incorporating a novel digital locking circuit for sequential laser-cavity mode matching. This system demonstrates rapid and precise hydrogen sulfide (H₂S) detection capability at parts-per-billion (ppb) concentration levels. Compared to traditional wavelength meters, our system delivers a 140-fold improvement in frequency interval precision (0.07 MHz, 0.027% relative uncertainty). Allan variance analysis under vacuum conditions demonstrates a sensitivity limit of 3 × 10⁻¹² cm⁻¹ at a 60-s averaging time. Validated through calibrated gas dilution tests, the analyzer detects a 4 ppb H₂S absorption signal with a signal-to-noise ratio (SNR) > 6, establishing a 2 ppb detection limit (3σ criterion). This innovative approach meets stringent industrial and environmental requirements, offering a significant advancement in trace gas-sensing technology. Full article

(This article belongs to the Special Issue Optical Sensing Technologies, Devices and Their Data Applications)

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11 pages, 2121 KiB

Open AccessArticle

Miniaturized and Wide-Range Microwave-Permittivity Sensor Based on Electromagnetic-Induced Transparency

by Siyuan Liu and Feng Xue

Photonics 2025, 12(3), 283; https://doi.org/10.3390/photonics12030283 - 19 Mar 2025

Viewed by 128

Abstract

In this paper, we had designed a microwave band permittivity sensor based on analog electromagnetic-induced transparency (A-EIT). By comparing the S-parameter changes of the tested sample before and after measurement, we can calculate the permittivity of the tested sample then distinguish material types [...] Read more.

In this paper, we had designed a microwave band permittivity sensor based on analog electromagnetic-induced transparency (A-EIT). By comparing the S-parameter changes of the tested sample before and after measurement, we can calculate the permittivity of the tested sample then distinguish material types with similar appearances. The transmission line had used impedance transformation structure, and the open circuit branch is vertically connected to the transmission line. The open circuit branch will have a coupling effect with the spiral cross structure and can also simulate the A-EIT phenomenon. The above design has potential applications in the miniaturization of sensors. Full article

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11 pages, 6291 KiB

Open AccessArticle

W-Band Ultra-Thin Broadband Metamaterial Absorber—Design and Applications

by Jianfei Zhu, Yiwei Sheng, Li Chen, Guoliang Gao, Minchao Shi, Zhiping Yin and Jun Yang

Photonics 2025, 12(3), 282; https://doi.org/10.3390/photonics12030282 - 19 Mar 2025

Viewed by 223

Abstract

This paper presents a flexible and broadband metamaterial absorber (MA) with a sandwich structure for W-band absorption. The MA uses a thin FR4 material as the dielectric layer and incorporates multiple patches of varying sizes as the top pattern layer. By optimizing the [...] Read more.

This paper presents a flexible and broadband metamaterial absorber (MA) with a sandwich structure for W-band absorption. The MA uses a thin FR4 material as the dielectric layer and incorporates multiple patches of varying sizes as the top pattern layer. By optimizing the dimensions and arrangement of the metal patches, an average absorption rate exceeding 94% is achieved across the 75–110 GHz frequency range, effectively covering the entire W-band. The MA, with a thickness of only 0.22 mm and a weight less than 600 g/m², is polarization-insensitive and maintains high absorption for TM waves within an incident angle of 45°. The structure is simple, low-cost, and compatible with PCB fabrication processes. The experimental results align well with the simulations and demonstrate effective absorbing performance in conformal applications, offering a new solution for flexible millimeter-wave absorption. Full article

(This article belongs to the Special Issue Advanced Photonics Metamaterials and Metasurfaces: Science and Applications, 2nd Edition)

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25 pages, 3555 KiB

Open AccessReview

Application of Organic Light-Emitting Diodes and Photodiodes in Optical Control and Detection of Neuronal Activity

by Marcin Kielar, Matthew Kenna, Philippe Blanchard and Pankaj Sah

Photonics 2025, 12(3), 281; https://doi.org/10.3390/photonics12030281 - 18 Mar 2025

Viewed by 424

Abstract

Optical techniques to study neuronal activity have greatly advanced the field of neuroscience over recent decades. Multichannel silicon-based recording probes combined with optical fibers allow for simultaneous recording and manipulation of neuronal activity that underpins cognitive processes and behavior. The recent development of [...] Read more.

Optical techniques to study neuronal activity have greatly advanced the field of neuroscience over recent decades. Multichannel silicon-based recording probes combined with optical fibers allow for simultaneous recording and manipulation of neuronal activity that underpins cognitive processes and behavior. The recent development of neural probes incorporating organic light-emitting diodes (OLEDs) and photodiode-based organic photodetectors (OPDs) offer additional advantages of biocompatibility, ultra-small footprint, multifunctionality, and low cost. These developments are ushering in a new generation of devices that are ideal for the interrogation of neuronal activity in vitro and in vivo. In this review, we discuss recent progress in OLED- and OPD-based neural probes, their applications in the optical control of neuronal function, and current challenges and prospects for the future. Full article

(This article belongs to the Special Issue Optical Imaging Innovations and Applications)

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14 pages, 10976 KiB

Open AccessArticle

Pump-Probe Detection of Diamond Ionization and Ablation Induced by Ultra-Fast Laser

by Jinpeng Duan, Yiying Song, Jiawei Wu, Shusen Zhao, Xuechun Lin and Yajun Pang

Photonics 2025, 12(3), 280; https://doi.org/10.3390/photonics12030280 - 18 Mar 2025

Viewed by 240

Abstract

Diamond, widely used in optoelectronic devices, plays a crucial role in improving performance through studies of its electronic structure and optoelectronic response. This study combines computational methods and experiments for analysis. Density functional theory calculates the diamond’s band structure and refractive index, while [...] Read more.

Diamond, widely used in optoelectronic devices, plays a crucial role in improving performance through studies of its electronic structure and optoelectronic response. This study combines computational methods and experiments for analysis. Density functional theory calculates the diamond’s band structure and refractive index, while the Keldysh formula determines the laser intensity at the critical plasma density by evaluating laser-induced free electron density. By integrating the coupled model with a multi-physics field associative assignment, the critical plasma length in the diamond is further simulated. Experimentally, pump-probe techniques examine the diamond’s response under varying pulse widths and energies. Results show that increasing laser energy extends both plasma and damage lengths. As pulse width increases, plasma length first decreases and then increases, while graphitization length shows the opposite trend. Experiments show that laser energy enhancement significantly expands the plasma morphology by enhancing the nonlinear ionization effect. When the pulse width exceeds the electron-lattice relaxation time, the lattice energy deposition triggers localized graphitization, which enhances the subsequent laser absorption, and the final plasma distribution shows a high spatial correlation with the graphitized regions. Full article

(This article belongs to the Topic Laser-Induced Damage Properties of Optical Materials)

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16 pages, 5691 KiB

Open AccessArticle

Single-View Encoding of 3D Light Field Based on Editable Field of View Gaussian Splatting

by Shizhou Shi, Chaoqun Ma, Jing Liu, Changpei Ma, Feng Zhang and Xiaoyu Jiang

Photonics 2025, 12(3), 279; https://doi.org/10.3390/photonics12030279 - 18 Mar 2025

Viewed by 234

Abstract

The paper presents an efficient light field image synthesis method based on single-viewpoint images, which can directly generate high-quality light field images from single-viewpoint input images. The proposed method integrates light field image encoding with the tiled rendering technique of 3DGS. In the [...] Read more.

The paper presents an efficient light field image synthesis method based on single-viewpoint images, which can directly generate high-quality light field images from single-viewpoint input images. The proposed method integrates light field image encoding with the tiled rendering technique of 3DGS. In the construction of the rendering pipeline, a viewpoint constraint strategy is adopted to optimize rendering quality, and a sub-pixel rendering strategy is implemented to improve rendering efficiency. Experimental results demonstrate that 8K light field images with 96 viewpoints can be generated in real time from end to end. The research presented in the paper provides a new approach for the real-time generation of high-resolution light field images, advancing the application of light field display technology in low-cost environments. Full article

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16 pages, 3670 KiB

Open AccessArticle

Incoherent Optical Neural Networks for Passive and Delay-Free Inference in Natural Light

by Rui Chen, Yijun Ma, Zhong Wang and Shengli Sun

Photonics 2025, 12(3), 278; https://doi.org/10.3390/photonics12030278 - 18 Mar 2025

Viewed by 284

Abstract

Optical neural networks are hardware neural networks implemented based on physical optics, and they have demonstrated advantages of high speed, low energy consumption, and resistance to electromagnetic interference in the field of image processing. However, most previous optical neural networks were designed for [...] Read more.

Optical neural networks are hardware neural networks implemented based on physical optics, and they have demonstrated advantages of high speed, low energy consumption, and resistance to electromagnetic interference in the field of image processing. However, most previous optical neural networks were designed for coherent light inputs, which required the introduction of an electro-optical conversion module before the optical computing device. This significantly hindered the inherent speed and energy efficiency advantages of optical computing. In this paper, we propose a diffraction algorithm for incoherent light based on mutual intensity propagation, and on this basis, we established a model of an incoherent optical neural network. This model is completely passive and directly performs inference calculations on natural light, with the detector directly outputting the results, achieving target classification in an all-optical environment. The proposed model was tested on the MNIST, Fashion-MNIST, and ISDD datasets, achieving classification accuracies of 82.32%, 72.48%, and 93.05%, respectively, with experimental verification showing an accuracy error of less than 5%. This neural network can achieve passive and delay-free inference in a natural light environment, completing target classification and showing good application prospects in the field of remote sensing. Full article

(This article belongs to the Topic Machine Learning in Communication Systems and Networks, 2nd Edition)

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23 pages, 4931 KiB

Open AccessArticle

Enhancing Selective Laser Melting Quality of High-Performance Aluminum Alloys Through Laser Parameter Optimization: A Coupled Multiphysics Simulation Study

by Yu Xia, Xing Peng, Shucheng Li, Haozhe Li, Bo Wang, Xinjie Zhao, Feng Shi, Shuo Qiao, Shiqing Li and Xiang Sun

Photonics 2025, 12(3), 277; https://doi.org/10.3390/photonics12030277 - 17 Mar 2025

Viewed by 314

Abstract

Laser additive manufacturing (AM) technology has become an important method for the manufacturing of high-performance aluminum alloy parts. However, the thermal effect of the molten pool and the defect formation mechanism are still the key issues restricting forming quality. To address this issue, [...] Read more.

Laser additive manufacturing (AM) technology has become an important method for the manufacturing of high-performance aluminum alloy parts. However, the thermal effect of the molten pool and the defect formation mechanism are still the key issues restricting forming quality. To address this issue, this paper systematically investigates the effects of key parameters such as laser power and pulse frequency on the thermal conductivity, kinetic behavior, and defect control of the molten pool through multi-physics coupled numerical simulation to provide theoretical support for improving the quality of components. It is found that the laser power and pulse frequency play a key role in the molten pool morphology and defect generation, with too low a power leading to non-fusion and too high a power triggering overheating and cracking, and too low a frequency leading to unstable morphology and too high a frequency triggering grain coarsening and thermal stress cracking. The optimized process parameters (power 700–800 W, frequency 72–100 KHz) effectively improved the melt pool morphology and reduced the defects. This study reveals the intrinsic mechanism of melt pool dynamics and defect formation, which provides important instructions for optimizing the aluminum alloy additive manufacturing process. Full article

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13 pages, 2741 KiB

Open AccessArticle

Quantum-Well-Embedded InGaN Quantum Dot Vertical-Cavity Surface-Emitting Laser and Its Photoelectric Performance

by Zinan Hua, Hailiang Dong, Zhigang Jia, Wei Jia, Lin Shang and Bingshe Xu

Photonics 2025, 12(3), 276; https://doi.org/10.3390/photonics12030276 - 17 Mar 2025

Viewed by 314

Abstract

An electrically injected vertical-cavity surface-emitting laser (VCSEL) with quantum-well-embedded InGaN quantum dots (QDs) as the active region was designed. The InGaN QD size and cavity length were optimized using PICS3D simulation software to achieve a high-performance InGaN QD-embedded VCSEL. A comparative analysis between [...] Read more.

An electrically injected vertical-cavity surface-emitting laser (VCSEL) with quantum-well-embedded InGaN quantum dots (QDs) as the active region was designed. The InGaN QD size and cavity length were optimized using PICS3D simulation software to achieve a high-performance InGaN QD-embedded VCSEL. A comparative analysis between the InGaN QD VCSEL and the traditional InGaN quantum well VCSEL was conducted, and the results demonstrated that the InGaN QD VCSEL achieved higher stimulated recombination radiation and internal quantum efficiency. The threshold current was reduced to 4 mA, corresponding to a threshold current density of 5.1 kA/cm², and the output power reached 4.4 mW at an injection current of 20 mA. A stable single-longitudinal-mode output was also achieved with an output wavelength of 436 nm. The proposed novel quantum-well-embedded QD active-region VCSEL was validated through theoretical simulations, confirming its feasibility. This study provides theoretical guidance and key epitaxial structural parameters for preparing high-performance VCSEL epitaxial materials. Full article

(This article belongs to the Section Lasers, Light Sources and Sensors)

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12 pages, 1371 KiB

Open AccessArticle

Multi-Beam-Energy Control Unit Based on Triple-Bend Achromats

by Liuyang Wu, Zihan Zhu, Bingyang Yan, Jiawei Yan and Haixiao Deng

Photonics 2025, 12(3), 275; https://doi.org/10.3390/photonics12030275 - 17 Mar 2025

Viewed by 248

Abstract

X-ray free electron lasers (XFELs) are the new generation of particle accelerator-based light sources, capable of producing tunable, high-power X-ray pulses that are increasingly vital across various scientific disciplines. Recently, continuous-wave (CW) XFELs driven by superconducting linear accelerators have garnered significant attention due [...] Read more.

X-ray free electron lasers (XFELs) are the new generation of particle accelerator-based light sources, capable of producing tunable, high-power X-ray pulses that are increasingly vital across various scientific disciplines. Recently, continuous-wave (CW) XFELs driven by superconducting linear accelerators have garnered significant attention due to their ability to enhance availability by supporting multiple undulator lines simultaneously. In this paper, we introduce a novel delay system comprising four triple-bend achromats (TBAs). This delay system was combined with fast kickers and can be employed to generate electron beams on a bunch-to-bunch basis in a CW-XFEL facility. Based on the parameters of the Shanghai High-Repetition-Rate XFEL and Extreme Light Facility, start-to-end simulations demonstrate that the TBA-based delay system achieves excellent electron beam qualities while providing a wide beam-energy-tuning range from 1.39 to 8 GeV. Full article

(This article belongs to the Special Issue Advances in Free-Electron Radiation Sources and Particle Accelerators: Current Research and Future Directions)

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9 pages, 2050 KiB

Open AccessArticle

A Fixed-Frequency Beam-Scanning Leaky-Wave Antenna with Circular Polarization for mmWave Application

by Xingying Huo, Yuchen Ma, Jiayi Liu and Qinghuai Zhou

Photonics 2025, 12(3), 274; https://doi.org/10.3390/photonics12030274 - 17 Mar 2025

Viewed by 247

Abstract

A period-reconfigurable leaky-wave antenna (LWA) with circular polarization (CP) and fixed-frequency beam scanning (FFBS) is developed in this article. Operating in the Ka-band, this antenna consists of a low-loss groove gap waveguide (GGW) as the slow-wave transmission structure, a circular split-ring patch [...] Read more.

A period-reconfigurable leaky-wave antenna (LWA) with circular polarization (CP) and fixed-frequency beam scanning (FFBS) is developed in this article. Operating in the Ka-band, this antenna consists of a low-loss groove gap waveguide (GGW) as the slow-wave transmission structure, a circular split-ring patch array on the top layer for radiation, and a slotted ground between them for energy coupling. Each slot is independently and electrically controlled by a pair of PIN diodes under the coupling slot. Thus, the period length of the patches can be manipulated and an LWA with CP and FFBS is achieved with −1th spatial harmonics radiated. The simulation results show that the bean-scanning range from 61° to 63° can be realized during the observation frequency band, with good circular polarization and a peak gain of 17.1 dBi, which is verified by the measurement. Full article

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17 pages, 3494 KiB

Open AccessArticle

Membrane-Mediated Conversion of Near-Infrared Amplitude Modulation into the Self-Mixing Signal of a Terahertz Quantum Cascade Laser

by Paolo Vezio, Andrea Ottomaniello, Leonardo Vicarelli, Mohammed Salih, Lianhe Li, Edmund Linfield, Paul Dean, Virgilio Mattoli, Alessandro Pitanti and Alessandro Tredicucci

Photonics 2025, 12(3), 273; https://doi.org/10.3390/photonics12030273 - 16 Mar 2025

Viewed by 532

Abstract

A platform for converting near-infrared (NIR) laser power modulation into the self-mixing (SM) signal of a quantum cascade laser (QCL) operating at terahertz (THz) frequencies is introduced. This approach is based on laser feedback interferometry (LFI) with a THz QCL using a metal-coated [...] Read more.

A platform for converting near-infrared (NIR) laser power modulation into the self-mixing (SM) signal of a quantum cascade laser (QCL) operating at terahertz (THz) frequencies is introduced. This approach is based on laser feedback interferometry (LFI) with a THz QCL using a metal-coated silicon nitride trampoline membrane resonator as both the external QCL laser cavity and the mechanical coupling element of the two-laser hybrid system. We show that the membrane response can be controlled with high precision and stability both in its dynamic (i.e., piezo-electrically actuated) and static state via photothermally induced NIR laser excitation. The responsivity to nanometric external cavity variations and robustness to optical feedback of the QCL LFI apparatus allows a highly sensitive and reliable transfer of the NIR power modulation into the QCL SM voltage, with a bandwidth limited by the thermal response time of the membrane resonator. Interestingly, a dual information conversion is possible thanks to the accurate thermal tuning of the membrane resonance frequency shift and displacement. Overall, the proposed apparatus can be exploited for the precise opto-mechanical control of QCL operation with advanced applications in LFI imaging and spectroscopy and in coherent optical communication. Full article

(This article belongs to the Special Issue The Three-Decade Journey of Quantum Cascade Lasers)

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8 pages, 1537 KiB

Open AccessCommunication

Ag-Grid and Ag-Nanowires Hybrid Transparent Electrodes to Improve Performance of Flexible Organic Light-Emitting Devices

by Hao Yang, Yangang Bi, Shirong Wang, Congfang Wang, Haipeng Wang, Gaoda Ye and Jing Feng

Photonics 2025, 12(3), 272; https://doi.org/10.3390/photonics12030272 - 16 Mar 2025

Cited by 1 | Viewed by 319

Abstract

Flexible transparent conductive electrodes, with high optical transmittance, electrical conductivity, and flexible stability, still challenge the commercial development of flexible organic light-emitting devices (OLEDs). In this work, a novel Ag-grid and Ag-nanowire (Ag-grid/AgNW) hybrid transparent conductive film was proposed with extraordinary optoelectronic and [...] Read more.

Flexible transparent conductive electrodes, with high optical transmittance, electrical conductivity, and flexible stability, still challenge the commercial development of flexible organic light-emitting devices (OLEDs). In this work, a novel Ag-grid and Ag-nanowire (Ag-grid/AgNW) hybrid transparent conductive film was proposed with extraordinary optoelectronic and mechanical performance. The hybrid film exhibited a low resistivity of 9 Ω/sq and a high transparency of 67.9% at the wavelength of 550 nm, as well as outstanding mechanical robustness by surviving over 5000 bending cycles. By applying the proposed Ag-grid/AgNW hybrid electrode in flexible OLEDs, the electroluminescence performance, flexibility, and mechanical reliability of the devices were significantly improved. Full article

(This article belongs to the Special Issue Advanced Methods in Exploring Light–Matter Interactions and Nonlinear Effects Optics Applications)

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16 pages, 10023 KiB

Open AccessArticle

Convolutional Neural Network-Based Fiber Optic Channel Emulator and Its Application to Fiber-Longitudinal Power Profile Estimation

by Daobin Wang, Kun Wen, Tiantian Bai, Ruiyang Xia, Zanshan Zhao and Guanjun Gao

Photonics 2025, 12(3), 271; https://doi.org/10.3390/photonics12030271 - 15 Mar 2025

Viewed by 348

Abstract

This paper proposes an accuracy enhancement method for fiber-longitudinal power profile estimation (PPE) based on convolutional neural networks (CNN). Two types of CNNs are designed. The first network treats different polarization streams identically and is denoted as CNN. The second network considers the [...] Read more.

This paper proposes an accuracy enhancement method for fiber-longitudinal power profile estimation (PPE) based on convolutional neural networks (CNN). Two types of CNNs are designed. The first network treats different polarization streams identically and is denoted as CNN. The second network considers the difference between the contributions of different polarization streams to the nonlinear phase shift and is denoted as enhanced CNN (ECNN). The numerical simulation results confirm the effectiveness of the method for a 64 Gbaud/s quadrature phase-shift keying (QPSK) polarization-division-multiplexed (PDM) coherent optical communication system with a fiber length of 320 km. The effects of finite impulse response (FIR) filter length, power into the fiber, and polarization mode dispersion on the PPE accuracy are examined. Finally, the results of the proposed method are monitored in the presence of several simultaneous power attenuation anomalies in the fiber optic link. It is found that the accuracy of the PPE substantially improves after using the proposed method, achieving a relative gain of up to 71%. When the modulation format is changed from QPSK to 16-ary quadrature amplitude modulation (16-QAM), and the fiber length is increased from 360 km to 480 km, the proposed method is still effective. This work provides a feasible solution for implementing fiber-longitudinal PPE, enabling significantly improved estimation accuracy in practical applications. Full article

(This article belongs to the Special Issue Advancements in Optical Sensing and Communication Technologies)

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9 pages, 5100 KiB

Open AccessArticle

High-Power KTiOAsO₄ Optical Parametric Oscillator at 300 Hz

by Tao Li, Jun Meng, Gaoyou Liu and Zhaojun Liu

Photonics 2025, 12(3), 270; https://doi.org/10.3390/photonics12030270 - 15 Mar 2025

Viewed by 334

Abstract

A high-power and high-repetition KTiOAsO₄ (KTA) optical parametric oscillator (OPO) was established in this study, with the adoption of plane-parallel and ring cavities. The pump was a high-power Nd:YAG master oscillator power amplifier (MOPA) system with a pulse repetition frequency (PRF) of [...] Read more.

A high-power and high-repetition KTiOAsO₄ (KTA) optical parametric oscillator (OPO) was established in this study, with the adoption of plane-parallel and ring cavities. The pump was a high-power Nd:YAG master oscillator power amplifier (MOPA) system with a pulse repetition frequency (PRF) of 300 Hz, and the corresponding beam quality factors were M_x² = 3.4 and M_y² = 3.2. In the plane-parallel cavity experiment, powers of 51.1 W (170 mJ) and 15.9 W (53 mJ) in the signal and idler were obtained, respectively. In terms of the average power of 1 μm of a pumped KTA OPO, to our knowledge, this is the highest average power for KTA OPO. The ring cavity was constructed to achieve lasers with both high power and beam quality. The output powers of the ring cavities for the signal and idler were 33.9 W (113 mJ) and 8.7 W (29 mJ), respectively, and the corresponding beam quality factors of the signal were M_x² = 5.3 and M_y² = 7.9. The 300 Hz 100 mJ class 1.54 μm laser with a beam quality factor of less than 10 is an ideal eye-safe light detection and ranging (LiDAR) source. Full article

(This article belongs to the Special Issue Recent Advances in Infrared Lasers and Applications)

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13 pages, 3864 KiB

Open AccessArticle

First Real-Time 221.9 Pb/S∙Km Transmission Capability Demonstration Using Commercial 138-Gbaud 400 Gb/S Backbone OTN System over Field-Deployed Seven-Core Fiber Cable with Multiple Fusion Splicing

by Jian Cui, Yu Deng, Zhuo Liu, Yuxiao Wang, Chen Qiu, Zhi Li, Chao Wu, Bin Hao, Leimin Zhang, Ting Zhang, Bin Wu, Chengxing Zhang, Weiguang Wang, Yong Chen, Kang Li, Feng Gao, Lei Shen, Lei Zhang, Jie Luo, Yan Sun, Qi Wan, Cheng Chang, Bing Yan and Ninglun Gu Show full author list Hide full author list

Photonics 2025, 12(3), 269; https://doi.org/10.3390/photonics12030269 - 14 Mar 2025

Viewed by 405

Abstract

The core-division-multiplexed (CDM) transmission technique utilizing uncoupled multi-core fiber (MCF) is considered a promising candidate for next-generation long-haul optical transport networks (OTNs) due to its high-capacity potential. For the field implementation of MCF, it is of great significance to explore its long-haul transmission [...] Read more.

The core-division-multiplexed (CDM) transmission technique utilizing uncoupled multi-core fiber (MCF) is considered a promising candidate for next-generation long-haul optical transport networks (OTNs) due to its high-capacity potential. For the field implementation of MCF, it is of great significance to explore its long-haul transmission capability using high-speed OTN transceivers over deployed MCF cable. In this paper, we investigate the real-time long-haul transmission capability of a deployed seven-core MCF cable using commercial 138-Gbaud 400 Gb/s backbone OTN transceivers with a dual-polarization quadrature phase shift keying (DP-QPSK) modulation format. Thanks to the highly noise-tolerant DP-QPSK modulation format enabled by the high baud rate, a real-time 256 Tb/s transmission over a 990.64 km (14 × 70.76 km) deployed seven-core fiber cable with more than 600 fusion splices is field demonstrated for the first time, which achieves a real-time capacity–distance product of 221.9 Pb/s∙km. Specifically, the long-haul CDM transmission is simulated by cascading the fiber cores of two segments of 70.76 km seven-core fibers. And dynamic gain equalizers (DGEs) are utilized to mitigate the impacts of stimulated Raman scattering (SRS) and the uneven gain spectra of amplifiers in broadband transmissions by equalizing the power of signals with different wavelengths. This field trial demonstrates the feasibility of applying uncoupled MCF in long-haul OTN transmission systems and will contribute to its field implementation in terrestrial fiber cable systems. Full article

(This article belongs to the Special Issue Optical Networking Technologies for High-Speed Data Transmission)

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19 pages, 1620 KiB

Open AccessArticle

Underwater Coherent Optical Wireless Communications with Electronic Beam Steering and Turbulence Compensation Using Adaptive Optics and Aperture Averaging

by Ali Derakhshandeh, Peter A. Hoeher and Stephan Pachnicke

Photonics 2025, 12(3), 268; https://doi.org/10.3390/photonics12030268 - 14 Mar 2025

Viewed by 420

Abstract

A novel approach to underwater optical wireless coherent communications using liquid crystal spatial light modulators (LC-SLMs) and an aperture averaging lens, in combination with optical phased-array (OPA) antennas, is presented. A comprehensive channel model that includes a wide range of underwater properties, including [...] Read more.

A novel approach to underwater optical wireless coherent communications using liquid crystal spatial light modulators (LC-SLMs) and an aperture averaging lens, in combination with optical phased-array (OPA) antennas, is presented. A comprehensive channel model that includes a wide range of underwater properties, including absorption, scattering, and turbulence effects, is employed to simulate the underwater optical wireless communication (UOWC) system in a realistic manner. The proposed system concept utilizes aperture averaging and adaptive optics techniques to mitigate the degrading effects of turbulence. Additionally, OPA antennas are integrated into the system to provide electronic beam steering capabilities, facilitating precise pointing, acquisition, and tracking (PAT) between mobile underwater vehicles. This integration enables high-speed and reliable communication links by maintaining optimal alignment. The numerical results show that under strong turbulence, our combined turbulence-compensation approach (LC-SLM plus aperture averaging) can extend the communication range by approximately threefold compared to a baseline system without compensation. For instance, at a soft-decision FEC threshold of

1.25 \times 10^{- 2}

, the maximum achievable link distance increases from around

10 m

to over

30 m

. Moreover, the scintillation index is reduced by more than

90 %

, and the bit error rate (BER) improves. Full article

(This article belongs to the Special Issue Advancements in Wireless Optical Communication: Integrating Visible Light and Beyond)

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16 pages, 1096 KiB

Open AccessArticle

Optimization of Voltage Requirements in Electro-Optic Polarization Controllers for High-Speed QKD Systems

by Hugo Filipe Costa, Armando Nolasco Pinto and Nelson Jesus Muga

Photonics 2025, 12(3), 267; https://doi.org/10.3390/photonics12030267 - 14 Mar 2025

Viewed by 306

Abstract

We present a framework to optimize the voltage range of electro-optic polarization controllers (EPC) in polarization-based quantum key distribution (QKD) subsystems. In this study, we consider an EPC capable of modifying both the phase difference between its fast and slow axes and the [...] Read more.

We present a framework to optimize the voltage range of electro-optic polarization controllers (EPC) in polarization-based quantum key distribution (QKD) subsystems. In this study, we consider an EPC capable of modifying both the phase difference between its fast and slow axes and the orientation of the fast axis. This capability allows it to transform any input state of polarization (SOP) into any desired output SOP on the Poincaré sphere using a single wave-plate. When multiple wave-plates are available, properly distributing the required polarization modulation across them effectively reduces the electronic demands, lowers the implementation costs, and enhances the polarization modulation speeds. This optimization is achieved through the application of multi-objective optimization (MOO) and wave-plate splitting techniques. Within a simulation model, using the calibration parameters from a commercially available six-wave-plate EPC, we determined the optimized voltage ranges required to achieve the six, four, and three SOPs typically used in polarization-based QKD protocols. Two voltage reference points are considered in our study: bias voltage points, which result in zero birefringence, and zero voltage points. For optimization procedures centered around the bias voltage points, we observe a significant reduction in the voltage range, from

\pm 37

V, for a single wave-plate, to approximately

\pm 6

V, for six wave-plates. Furthermore, using wave-plate splitting techniques, we conclude that only two independent wave-plates (four variables) need to be considered in our model to achieve optimized results, which contributes to the efficient design of polarization-based QKD subsystems by minimizing voltage transitions while ensuring precise SOP control, ultimately enabling cost-effective and high-speed polarization modulation. Full article

(This article belongs to the Special Issue Current Advances on Applications of Optics and Photonics – Selected Papers from the 6th International Conference on Applications of Optics and Photonics, AOP2024)

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13 pages, 3806 KiB

Open AccessArticle

Impact of Sn Particle-Induced Mask Diffraction on EUV Lithography Performance Across Different Pattern Types

by Seungchan Moon, Dong Gi Lee, Jinhyuk Choi, Junho Hong, Taeho Lee, Yasin Ekinci and Jinho Ahn

Photonics 2025, 12(3), 266; https://doi.org/10.3390/photonics12030266 - 14 Mar 2025

Viewed by 391

Abstract

This study investigates the differences in the lithographic impact of particles on the pellicle surface depending on the type of extreme ultraviolet (EUV) mask pattern. Using an EUV ptychography microscope, we analyzed how mask imaging performance is affected by locally obstructed mask diffraction [...] Read more.

This study investigates the differences in the lithographic impact of particles on the pellicle surface depending on the type of extreme ultraviolet (EUV) mask pattern. Using an EUV ptychography microscope, we analyzed how mask imaging performance is affected by locally obstructed mask diffraction caused by a 10 μm × 10 μm patterned tin particle intentionally fabricated on the pellicle surface. The resulting critical dimension variations were found to be approximately three times greater in line-and-space patterns than in contact hole patterns. Based on these findings, we recommend defining the critical size of particles according to the mask pattern type to optimize lithographic quality. Full article

(This article belongs to the Special Issue Computational Imaging for Semiconductor Devices Metrology Applications)

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19 pages, 7583 KiB

Open AccessArticle

Design and Processing of Hard and Self-Lubricating NiCr/hBN-cBN Composite Coatings by Laser Cladding: Investigation of Microstructure, Hardness, and Wear

by Morteza Taheri and Kourosh Shirvani

Photonics 2025, 12(3), 265; https://doi.org/10.3390/photonics12030265 - 13 Mar 2025

Viewed by 479

Abstract

Hardness and wear resistance are the requirements of nickel-based superalloys used in gas turbine blades. This study uses laser cladding technology to develop three types of wear-resistant coatings—NiCr-2%hBN, NiCr-12%cBN, and NiCr-2%hBN-12%cBN—on GTD-111 superalloy. The above coatings’ microstructure, microhardness, and tribological behavior were systematically [...] Read more.

Hardness and wear resistance are the requirements of nickel-based superalloys used in gas turbine blades. This study uses laser cladding technology to develop three types of wear-resistant coatings—NiCr-2%hBN, NiCr-12%cBN, and NiCr-2%hBN-12%cBN—on GTD-111 superalloy. The above coatings’ microstructure, microhardness, and tribological behavior were systematically characterized by scanning electron microscope, hardness tester, pin-on-disc wear device, and three-dimensional profiles. The hardness test results showed that the hBN coating has the lowest hardness (692 HV) due to its layered structure, and the hBN-cBN coating has the highest hardness (992 HV) due to its complex structure and the creation of inhomogeneous nucleation centers in the coating. The wear test results showed that the hBN coating has a lower coefficient of friction (COF) (0.49) than the hard cBN coating (0.53) due to its lubricating properties. Meanwhile, the wear rate of the hBN coating is lower than the wear rate of the hard cBN due to the weak forces of one in the B-N bond. However, the wear test results of hBN-cBN coating showed that the effects of hBN and the high hardness of cBN cause the formation of a coating with the lowest wear rate (0.22 × 10⁻⁶ mm³/N·m), COF (0.41), fluctuation, wear depth (17.2 µm), and wear volume loss (0.32 × 10⁵ µ³) compared to the other two coatings. In addition, in the hBN-cBN coating, due to the greater driving force for the inhomogeneous nucleation of the melt, a larger area of equiaxed grains was formed, which in turn had a significant effect on increasing the wear resistance. Full article

(This article belongs to the Section Lasers, Light Sources and Sensors)

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12 pages, 2450 KiB

Open AccessArticle

A Generalized Floquet Hamiltonian Method for Dispersive Photonic Time Crystals

by Guangquan Lu and Neng Wang

Photonics 2025, 12(3), 264; https://doi.org/10.3390/photonics12030264 - 13 Mar 2025

Viewed by 408

Abstract

We present a generalized Floquet Hamiltonian method for dispersive photonic time crystals (PTCs), a class of time-varying media with time-periodic plasma frequencies and damping rates. Using the time-independent Floquet Hamiltonian method, we successfully obtained the quasienergy band dispersions of dispersive PTCs, which show [...] Read more.

We present a generalized Floquet Hamiltonian method for dispersive photonic time crystals (PTCs), a class of time-varying media with time-periodic plasma frequencies and damping rates. Using the time-independent Floquet Hamiltonian method, we successfully obtained the quasienergy band dispersions of dispersive PTCs, which show excellent agreement with the temporal transfer matrix method (TTMM) results when applied to temporal multilayers. Furthermore, our approach overcomes the limitations of TTMM by handling arbitrary time interfaces and providing access to both right and left eigenstates, enabling deeper insights into the properties of PTCs. Ultimately, our method significantly advances the analytical and numerical investigations into dispersive time-varying media. Full article

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25 pages, 5863 KiB

Open AccessArticle

A Reconfigurable 1x2 Photonic Digital Switch Controlled by an Externally Induced Metasurface

by Alessandro Fantoni and Paolo Di Giamberardino

Photonics 2025, 12(3), 263; https://doi.org/10.3390/photonics12030263 - 13 Mar 2025

Viewed by 363

Abstract

This work reports the design of a 1x2 photonic digital switch controlled by an electrically induced metasurface, configurated by a rectangular array of points where the refractive index is locally changed through the application of an external bias. The device is simulated using [...] Read more.

This work reports the design of a 1x2 photonic digital switch controlled by an electrically induced metasurface, configurated by a rectangular array of points where the refractive index is locally changed through the application of an external bias. The device is simulated using the Beam Propagation Method (BPM) and Finite Difference Time Domain (FDTD) algorithms and the structure under evaluation is an amorphous silicon 1x2 multimode interference (MMI), joined to an arrayed Metal Oxide Semiconductor (MOS) structure Al/SiNx/a-Si:H/ITO to be used in active-matrix pixel fashion to control the output of the switch. MMI couplers, based on self-imaging multimode waveguides, are very compact integrated optical components that can perform many different splitting and recombining functions. The input–output model has been defined using a machine learning approach; a high number of images have been generated through simulations, based on the beam propagation algorithm, obtaining a large dataset for an MMI structure under different activation maps of the MOS pixels. This dataset has been used for training and testing of a machine learning algorithm for the classification of the MMI configuration in terms of binary digital output for a 1x2 switch. Also, a statistical analysis has been produced, targeting the definition of the most incident-activated pixel for each switch operation. An optimal configuration is proposed and applied to demonstrate the operation of a digital cascaded switch. This proof of concept paves the way to a more complex device class, supporting the recent advances in programmable photonic integrated circuits. Full article

(This article belongs to the Special Issue New Perspectives in Semiconductor Optics)

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13 pages, 1440 KiB

Open AccessArticle

Evaluation of an Augmented Reality-Based Visual Aid for People with Peripheral Visual Field Loss

by Carolina Ortiz, Ricardo Bernardez-Vilaboa, F. Javier Povedano-Montero, María Paz Álvaro-Rubio and Juan E. Cedrún-Sánchez

Photonics 2025, 12(3), 262; https://doi.org/10.3390/photonics12030262 - 13 Mar 2025

Viewed by 586

Abstract

Augmented reality (AR) technologies can improve the quality of life of individuals with visual impairments. The current study evaluated the efficacy of Retiplus, a new AR-based low-vision device, which was designed to enhance spatial awareness and visual function in patients with peripheral visual [...] Read more.

Augmented reality (AR) technologies can improve the quality of life of individuals with visual impairments. The current study evaluated the efficacy of Retiplus, a new AR-based low-vision device, which was designed to enhance spatial awareness and visual function in patients with peripheral visual field loss. Thirteen patients diagnosed with retinitis pigmentosa (RP) participated in this study. The patients’ visual acuity, visual field, and subjective perception of peripheral vision and mobility were assessed both without and with the AR aid, following a training period consisting of five 1 h sessions. The results showed a significant expansion of the visual field (VF) in all four quadrants (right, left, upper, and lower) with a greater horizontal diameter enlargement (21.38° ± 12.94°) than vertical (15° ± 10.08°), with a statistically significant difference. However, the increase in VF was accompanied by a modest reduction in visual acuity due to the minification of the image on the display. Patient feedback also highlighted significant benefits on the ability to perform activities of daily living (ADL) in low-light environments and improved spatial orientation, suggesting that the AR system is helpful for some limitations imposed by patients’ conditions. These findings underscore the importance of optimizing AR technology to support visually impaired populations. Full article

(This article belongs to the Special Issue Advances in Optometric and Ophthalmic Technologies: Innovations and Applications)

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