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Hierarchical pore structure with a confined resonant mode for improving the solar energy utilizing efficiency of ultra-thin perovskite solar cells Opt. Express (IF 3.8) Pub Date : 2024-04-24 Xinping Zhang, Jiaxin Du, Fuqiang Wang, Zenghui Xu, Xiang Li, Huaxu Liang, and Hongliang Yi
The perovskite solar cell (PSC) has the benefits of flexibility, inexpensiveness, and high efficiency, and has important prospective applications. However, serious optical losing and low solar energy-utilizing efficiency remain a challenge for the ultra-thin PSCs because of the interface reflection of traditional planar structure. In this study, a hierarchical pore structure with a confined resonant
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Ghost image analysis for pancake virtual reality systems Opt. Express (IF 3.8) Pub Date : 2024-04-24 Zhenyi Luo, Yuqiang Ding, Qian Yang, and Shin-Tson Wu
Pancake optics (also known as polarization-based catadioptric system) has been widely used as the imaging lens for virtual reality (VR) and mixed reality (MR) headsets because of its compact formfactor and excellent image quality. However, such a folded pancake optics not only dramatically lowers the optical efficiency to 25% because of the utilization of a half mirror, but also suffers from ghost
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Radiation hardness of open Fabry-Pérot microcavities Opt. Express (IF 3.8) Pub Date : 2024-04-24 Fernanda C. Rodrigues-Machado, Erika Janitz, Simon Bernard, Hamed Bekerat, Malcolm McEwen, James Renaud, Shirin A. Enger, Lilian Childress, and Jack C. Sankey
High-finesse microcavities offer a platform for compact, high-precision sensing by employing high-reflectivity, low-loss mirrors to create effective optical path lengths that are orders of magnitude larger than the device geometry. Here, we investigate the radiation hardness of Fabry-Pérot microcavities formed from dielectric mirrors deposited on the tips of optical fibers. The microcavities are irradiated
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Development of a biophotonic fiber sensor using direct-taper and anti-taper techniques with seven-core and four-core fiber for the detection of doxorubicin in cancer treatment Opt. Express (IF 3.8) Pub Date : 2024-04-25 Xiangshan Li, Ragini Singh, Bingyuan Zhang, Santosh Kumar, and Guoru Li
Doxorubicin (DOX) is an important drug for cancer treatment, but its clinical application is limited due to its toxicity and side effects. Therefore, detecting the concentration of DOX during treatment is crucial for enhancing efficacy and reducing side effects. In this study, the authors developed a biophotonic fiber sensor based on localized surface plasmon resonance (LSPR) with the multimode fiber
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Delivery of nanosecond laser pulses by multi-mode anti-resonant hollow core fiber at 1 µm wavelength Opt. Express (IF 3.8) Pub Date : 2024-04-25 Meng Zhao, Fei Yu, Dakun Wu, Xinyue Zhu, Si Chen, Meng Wang, Minzhe Liu, Kun Zhao, Ruizhan Zhai, Zhongqing Jia, and Jonathan Knight
In this paper we explore the application of low-loss multimode anti-resonant hollow-core fiber (MM-AR-HCF) in the delivery of nanosecond laser pulses at 1 µm wavelength. MM-AR-HCF with large core offers a rich content of low-loss higher-order modes which plays a key role in the efficient coupling and transmission of high-power laser of low beam quality. In the experiment, laser pulses of an average
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Magneto-chiral backscatterings by rotationally symmetric nonreciprocal structures Opt. Express (IF 3.8) Pub Date : 2024-04-25 Chunchao Wen, Jianfa Zhang, Shiqiao Qin, Zhihong Zhu, and Wei Liu
It was proved that the joint operation of electromagnetic reciprocity and n-fold (n ≥ 3) rotational symmetry would secure arbitrary polarization-independent backscattering efficiency [Phys. Rev. B 103(4), 045422 (2021) [CrossRef] ]. Here we remove the restriction of reciprocity and study the backscatterings of plane waves by rotationally symmetric magneto-optical structures, with collinear incident
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Single-photon sources based on stepwise optimized binary-tree multiplexers Opt. Express (IF 3.8) Pub Date : 2024-04-24 Peter Adam and Matyas Mechler
We propose a spatially multiplexed single-photon source where the structure of the applied binary-tree multiplexer is optimized systematically during its construction. Along the building procedure of this type of multiplexer, the position of a binary photon router appended to the tree in a step of the expansion is determined by taking into account the current achievable single-photon probability of
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High efficiency and stability of perovskite solar cells prepared by alkali metal interfacial modification Opt. Express (IF 3.8) Pub Date : 2024-04-23 Wenwen Zhang, Yuchao Song, Heng Zhang, Anpeng La, and Yanguo Lu
Perovskite solar cells (PSCs) have attracted much attention at home and abroad due to their excellent photoelectric properties. Defects in the electron transport layer (ETL) and ETL/perovskite interface greatly affect the power conversion efficiency (PCE) and stability of PSCs. In the paper, the surface of tin dioxide (SnO2) ETL was modified by an alkali metal salt (NaBr, KBr, and RbBr) solution to
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Measuring non-linear Faraday rotation in cold atoms in presence of persistent transverse fields using tunable differential imaging Opt. Express (IF 3.8) Pub Date : 2024-04-23 Sujit Garain, Surya Narayan Sahoo, and Ashok K. Mohapatra
Non-linear Faraday rotation in cold atoms promises precision magnetometry due to narrower magnetic resonance linewidth compared to the linear Faraday effect. Imaging techniques based on linear Faraday effect have emerged as a tool to characterize the dynamics of ultracold atomic clouds. Using a camera instead of balanced detectors, we can obtain the spatial distribution of polarization rotation in
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Analysis of extreme ultraviolet radiation and hydrodynamics simulation at the core of laser-produced nickel plasmas Opt. Express (IF 3.8) Pub Date : 2024-04-23 Siqi He, Qi Min, Yanhong Wu, Xingbang Liu, Chaowei He, Shiquan Cao, Qikun Pan, Jin Guo, Fei Chen, Denghong Zhang, Maogen Su, and Chenzhong Dong
The non-uniformity and transient nature of laser-produced plasma are critical factors that affect the analysis of the extreme ultraviolet spectra of highly charged ions and the diagnosis of plasma states. This paper systematically investigates the characteristics of extreme ultraviolet radiation and the hydrodynamic evolution of laser-produced nickel plasmas from two perspectives: high-spatio-temporal-resolution
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Stochastic ray tracing for Fresnel diffraction Opt. Express (IF 3.8) Pub Date : 2024-04-23 Keita Seto
We propose stochastic ray tracing for laser beam propagation in Fresnel diffraction to find the duality between wave and ray representations. We transform from the Maxwell equations to the Schrödinger equation for a monochromatic laser beam in the slowly varying envelope approximation. The stochastic ray tracing method interprets this Schrödinger equation as a stochastic process, of an analogy of Nelson’s
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Correction of the wavelength error in transmission of a full-color holographic 3D image Opt. Express (IF 3.8) Pub Date : 2024-04-23 Chang-Joo Lee, Hirohito Nishi, and Kyoji Matsushima
When a digital holographic image represented by a sampled wavefield is transmitted and the wavelength used in the three-dimensional (3D) display devices does not agree exactly with the wavelength of the original image data, the reconstructed 3D image will differ slightly from the original. This slight change is particularly problematic for full-color 3D images reconstructed using three wavelengths
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Picosecond laser-driven coded-source radiography with high resolution and contrast Opt. Express (IF 3.8) Pub Date : 2024-04-23 Mengting Li, Tiankui Zhang, Shaoyi Wang, Minghai Yu, Fang Tan, Yonghong Yan, Yue Yang, Jiaxing Wen, Yuchi Wu, Jingqin Su, Weimin Zhou, and Yuqiu Gu
The X-ray sources for Compton radiography of ICF experiments are generated by using intense picosecond lasers to irradiate wire targets. The wire diameter must be designed thin enough, for example ∼ 10 µm in many published works, to comply a high spatial resolution. This results in a low laser-target interception, which limits the photon yield. We investigated a technique of coded-source radiography
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Compressive sensing-based multi-focus line-scanning two-photon microscopy for fast 3D imaging Opt. Express (IF 3.8) Pub Date : 2024-04-23 Gan Liu, Bingxu Chen, Zezhi Tian, Qiuyuan Zhong, and Shih-Chi Chen
Fast 3D volume imaging methods have been playing increasingly important roles in biological studies. In this article, we present the design and characterization of a multi-focus line-scanning two-photon microscope. Specifically, a digital micromirror device (DMD) is employed to generate a randomly distributed focus array on a plane (i.e., x-z) via binary holography. Next, a galvanometric mirror scans
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Frequency drift characterization of a laser stabilized to an optical fiber delay line Opt. Express (IF 3.8) Pub Date : 2024-04-23 Irene Barbeito Edreira, Radan Slavík, Jayanta K. Sahu, Martín Núñez-Velázquez, Louise Wright, Marco Schioppo, and Giuseppe Marra
Lasers stabilized to optical fiber delay lines have been shown to deliver a comparable short-term (<1 s) frequency noise performance to that achieved by lasers stabilized to ultra-low expansion (ULE) cavities, once the linear frequency drift has been removed. However, for continuous stable laser operations, the drift can be removed only when it can be predicted, e.g., when it is linear over very long
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Phase demodulation method of high line density grating interferometric signal based on wavelet transform Opt. Express (IF 3.8) Pub Date : 2024-04-23 Zhangning Xie, Tao Jin, Lihua Lei, Zichao Lin, Dongbai Xue, Xiong Dun, Xiao Deng, and Xinbin Cheng
The increasing line density of the reference grating and the accelerating miniaturization of ultra-precision displacement measurement technology necessitate more stable interferometric signal processing methods for high line density gratings, particularly in low signal-to-noise ratio scenarios. This paper presents a phase demodulation method for dynamic interferometric signals for high line density
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Exploring the pyro-phototronic effect for giant lateral photoresponse in an ITO/CdS/Si heterojunction position-sensitive detector Opt. Express (IF 3.8) Pub Date : 2024-04-23 Guojuan Zhang, Siyang Guo, Tao Zhang, Qing Wang, Zicai Zhang, Jihong Liu, Shufang Wang, and Shuang Qiao
The demand for a high-performance position sensitive detector (PSD), a novel type of photoelectric sensor, is increasing due to advancements in digitization and automation technology. Cadmium sulfide (CdS), a non-centrosymmetric material, holds significant potential in photoelectric devices. However, the pyroelectric effect of CdS in PSDs and its influence on lateral photoresponse are still unknown
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Single-beam three-axis SERF atomic magnetometer based on coordinate system rotation Opt. Express (IF 3.8) Pub Date : 2024-04-23 Jialong Zhang, Tianpeng Chen, Chen Wei, Zhonghua Ou, Huimin Yue, and Yong Liu
We propose what we believe to be a new single-beam three-axis spin exchange relaxation free (SERF) vector atomic magnetometer scheme based on coordinate system deflection. A theoretical model for the system response under arbitrary angle deflection was established for the first time, and the system response at different angles was simulated and analyzed. The simulation results show that the system
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Reconfigurable multi-channel microwave photonic receiver for a multi-band signal based on cascaded microring resonator banks Opt. Express (IF 3.8) Pub Date : 2024-04-23 Ziyang Lu, Jiachen Li, Feifei Yin, Hongwei Chen, Sigang Yang, and Minghua Chen
What we believe to be a novel reconfigurable multi-channel microwave photonic (MWP) receiver for multi-band RF signal is demonstrated for the first time, to the best of our knowledge. A reconfigurable MWP signal processing chip based on two cascaded microring filter banks is employed in the proposed receiver, which slices the multi-band RF input into several narrow band signals and selects optical
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Unveiling second harmonic generation from femtosecond-laser microstructured Nd:YAG crystal Opt. Express (IF 3.8) Pub Date : 2024-04-23 Nuria Sevilla-Sierra, Javier R. Vázquez de Aldana, Carolina Romero, Xavier Mateos, and Ignacio Lopez-Quintas
In this work we apply second harmonic microscopy to the analysis of damage tracks inscribed by femtosecond laser irradiation in a Nd:YAG crystal. While second harmonic generation is not expected in the bulk of this centrosymmetric material, the 2D and 3D images obtained via second harmonic microscopy show that the induced micro-modification of the crystal structure leads to a localized generation of
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Laser-induced plasma micromachining on surfaces parallel to the incident laser in different solutions Opt. Express (IF 3.8) Pub Date : 2024-04-23 Hailong Zhang, Rui Zhang, Lou Gao, Zhi Yang, Yang Mao, Nan Zhao, Jian Lu, and Xingsheng Wang
Laser-induced plasma micromachining (LIPMM) is an advanced technology that utilizes the plasma generated from laser breakdown to remove material, thereby facilitating the fabrication of microstructures. This paper explores the use of LIPMM on 304 stainless steel surfaces parallel to the laser beam in different solutions, focusing on the impact of the liquid environment on the machining process. It
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4.1 W continuous-wave and broadly wavelength tunable Tm-doped laser in 2.1-2.4 µm spectral region based on vibronic and electronic transitions Opt. Express (IF 3.8) Pub Date : 2024-04-23 Xue Zhou, Jiajia Mao, Ping Hu, Jiatong Li, Jingkun Zhang, Hongkun Nie, Tao Li, Tianli Feng, Baitao Zhang, Jingliang He, and Kejian Yang
Efficient diode-pumped continuous-wave (CW) and wavelength tunable Tm:YAP lasers based on the vibronic and electronic transitions are investigated. A total maximum output power of 4.1 W is achieved with multi-wavelength output around 2162 nm and 2274 nm, corresponding to a slope efficiency of 29.8% for a 3 at. % Tm:YAP crystal. A maximum output power of 2.48 W with a slope efficiency of 25.4% is obtained
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Temporal contrast enhancement of a Ti:Sapphire laser by nonlinear Fourier filtering Opt. Express (IF 3.8) Pub Date : 2024-04-23 Sándor Szatmári, Tamás Nagy, Rita Dajka, Miklós Á. Kedves, Márk Aladi, and István B. Földes
Temporal cleaning of high-power infrared (IR) pulses generated by a Ti:Sapphire system is demonstrated by the use of the Nonlinear Fourier Filtering (NFF) method. In a proof-of-principle experiment suppression of up to 1000 is achieved for the temporal pedestal prior to the main pulse, with a moderate (20-25%) overall throughput. This includes the same suppression ratio for the picosecond coherent
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Investigation of optical polarization characteristics of ultraviolet-C AlGaN multiple quantum wells by angle-resolved cathodoluminescence Opt. Express (IF 3.8) Pub Date : 2024-04-23 Honglin Gong, Lihong Zhu, Yaqi Cai, Renlong Yang, Weijie Guo, Huanting Chen, Zhong Chen, and Yijun Lu
AlGaN-based ultraviolet-C (UV-C) light-emitting diodes (LEDs) face challenges related to their extremely low external quantum efficiency, which is predominantly attributed to the remarkably inadequate transverse magnetic (TM) light extraction efficiency (LEE). In this study, we employ angle-resolved cathodoluminescence (ARCL) spectroscopy to assess the optical polarization of (0001)-oriented AlGaN
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Conformal frequency selective rasorber in S, C, X-band with low backward-scattering Opt. Express (IF 3.8) Pub Date : 2024-04-23 Yang Fu, Fan Ding, Jing Jin, Houyuan Cheng, Yuejie Yang, Xiaofeng Zhou, Yilin Dai, and Helin Yang
In this paper, a polarization-insensitive high transmittance bandpass filter with low radar cross section (RCS) in both S- and X-band is proposed. This is the first study to use the partition layout loading approach for conformal structures with transmissive windows, reducing the operating band RCS. Curved structures have stronger radiation at a smaller angle to the incident wave, and that is how their
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Design of polarization convert metasurface element with high angle stability Opt. Express (IF 3.8) Pub Date : 2024-04-23 Haoran Ye and Yan Zhang
This paper proposed a high angle stability polarization convert metasurface element. The element has one dielectric substrate with the bending lines on the top layer and metallic ground on the bottom layer. A method of priority optimize polarization conversion ratio(PCR) under oblique incident angle based on impedance analysis is proposed to realize high angle stability. And the proposed element can
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Heterogeneously integrated InGaP/Si waveguides for nonlinear photonics Opt. Express (IF 3.8) Pub Date : 2024-04-23 Albert Peralta Amores and Marcin Swillo
The heterogeneous integration of III-V semiconductors with the Silicon platform enables the merging of photon sources with Silicon electronics while allowing the use of Silicon mature processing techniques. However, the inherent sufficient quality of III-Vs’ native oxides made imperative the use of deposited interfacial oxide layers or adhesives to permit the bonding. Here we present a novel approach
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Rayleigh length extension in long-distance free-space optical communications based on lens group optimization Opt. Express (IF 3.8) Pub Date : 2024-04-23 Jinfeng Liu, Chengkun Cai, Shuo Wang, and Jian Wang
In the field of high-speed data transmission, wireless optical communications provide a paradigm shift from the conventional tethered connections, offering promising bandwidth and minimal latency. The cornerstone of such systems lies in their ability to precisely control the propagation of Gaussian beams, which are favored due to their inherent properties of minimal divergence and high spatial coherence
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Dual-polarization MZM-based photonic nonlinear analog self-interference cancellation for in-band full-duplex radios Opt. Express (IF 3.8) Pub Date : 2024-04-23 Joungmoon Lee, Jinwoo Park, Inho Ha, and Sang-Kook Han
In this paper, we propose a dual-polarization Mach-Zehnder modulator-based photonic nonlinear analog self-interference cancellation (SIC) technique for in-band full duplex (IBFD) systems. By using the proposed technique, an arbitrary 4th order nonlinear transfer function can be generated, meaning the performance limitation caused by the nonlinearity of the analog SIC circuit can be overcome by imitating
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Compensation schemes for uneven illumination and LED light-emitting instability in optical camera communication system Opt. Express (IF 3.8) Pub Date : 2024-04-23 Shaoxi Ji, Aiying Yang, Wenpeng Fan, Lihui Feng, Zhenrong Zhang, and Minglun Zhang
In order to increase the data rate of the optical camera communication (OCC) system, the 8-composite-amplitude-shift-keying modulation (8CASK) OCC system is used in this work. However, if the static decision thresholds are employed to demodulate multi-level ASK signal, uneven illumination of LED lamps and LED light-emitting instability lead to the fluctuation of the gray range in the picture and degrade
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Fluorescent antenna based on Förster resonance energy transfer (FRET) for optical wireless communications Opt. Express (IF 3.8) Pub Date : 2024-04-23 Cuiwei He, Steve Collins, and Hideyuki Murata
The use of fluorescent antennas in optical wireless communications (OWC) has been demonstrated previously, and it has been shown that it is an efficient method for enhancing receiver performance, providing both signal gain and a wide field of view (FoV). To achieve a high concentration gain at the receiver output, the selected fluorophores should have a high photoluminescence quantum yield (PLQY),
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Design and characterization of a self-matching photonic lantern for all few-mode fiber laser systems Opt. Express (IF 3.8) Pub Date : 2024-04-23 Li Zhao, Wei Li, Yunhao Chen, Ting Yu, Enming Zhao, and Jianing Tang
We model and demonstrate a self-matching photonic lantern (SMPL) device, which is designed to address the constraint of limited transverse modes generated by fiber lasers. The SMPL incorporates a FMF into the array at the input end of a traditional photonic lantern. The few-mode fiber at the output end is specifically configured to align with the few-mode fiber at the input, therefore named as SMPL
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Polarimetric measurement of temporal coherence in electromagnetic light beams Opt. Express (IF 3.8) Pub Date : 2024-04-23 Jyrki Laatikainen, Kimmo Saastamoinen, Andreas Norrman, José J. Gil, Ari T. Friberg, and Tero Setälä
We present a method to determine the degree of temporal coherence of a quasimonochromatic vectorial light beam by polarimetric measurements. More specifically, we employ Michelson’s interferometer in which the polarization Stokes parameters of the output (interference) beam are measured as a function of the time delay. Such a measurement enables us to deduce the magnitudes of the coherence (two-time)
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Spectral speckle displacement in defocused and tilted imaging systems Opt. Express (IF 3.8) Pub Date : 2024-04-23 Patrick Laux, Annelie Schiller, Alexander Bertz, Daniel Carl, and Stephan Reichelt
Speckle patterns offer valuable insights into the surface characteristics or the characteristics of the light generating the speckle. One possible way to extract this information is via spectral speckle correlation (SSC). The cross-correlation between two speckle fields, generated at different wavelengths, can be used for example to determine the roughness of the illuminated surface. Taking defocused
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Tunable polarization control with self-assembled arrays of anisotropic plasmonic coaxial nanocavities Opt. Express (IF 3.8) Pub Date : 2024-04-23 Haibin Ni, An Ping, Tong Cai, Bo Ni, Jianhua Chang, and Alexey V. Krasavin
Polarization control with nanostructures having a tunable design and allowing inexpensive large-scale fabrication is important for many nanophotonic applications. For this purpose, we developed and experimentally demonstrated nanostructured plasmonic surfaces based on hexagonal arrays of anisotropic coaxial nanocavities, which can be fabricated by a low-cost self-assembled nanosphere lithography method
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Photon counting Raman spectroscopy: a benchmarking study vs surface plasmon enhancement Opt. Express (IF 3.8) Pub Date : 2024-04-22 Yehong Li, Santosh Kumar, Tianhang Huo, Henry Du, and Yu-Ping Huang
We demonstrate a single-photon counting Raman spectroscope and benchmark it against conventional and surface-enhanced Raman spectroscopy. For direct comparison without ambiguity, we use the same solutions of Rhodamine 6G and a common optical setup with either a spectrometer or an acousto-optic tunable filter, whereas the surface enhancement is realized with immobilized Ag nanoparticles. Our results
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Highly integrated automatic injection terahertz microfluidic biosensor based on metasurface and LT-GaAs photoconductive antenna Opt. Express (IF 3.8) Pub Date : 2024-04-23 Qinghao Meng, Yuhan Zhao, Xueyan Wang, Bo Su, Shengbo Zhang, Hailin Cui, and Cunlin Zhang
In this paper, a highly integrated terahertz (THz) biosensor is proposed and implemented, which pioneered the preparation of low-temperature gallium arsenide (LT-GaAs) thin film photoconductive antenna (PCA) on the sensor for direct generation and detection of THz waves, simplifying complex terahertz time-domain spectroscopy (THz-TDS) systems. A latch type metasurface is deposited in the detection
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Reconstruction method suitable for fast CT imaging Opt. Express (IF 3.8) Pub Date : 2024-04-23 Xueqin Sun, Yu Li, Yihong Li, Sukai Wang, Yingwei Qin, and Ping Chen
Reconstructing computed tomography (CT) images from an extremely limited set of projections is crucial in practical applications. As the available projections significantly decrease, traditional reconstruction and model-based iterative reconstruction methods become constrained. This work aims to seek a reconstruction method applicable to fast CT imaging when available projections are highly sparse
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Riemannian color difference metric for spatial sinusoidal color variations Opt. Express (IF 3.8) Pub Date : 2024-04-23 Patrick Candry, Patrick De Visschere, and Kristiaan Neyts
Several studies report on the sensitivity of human vision to static spatial sinusoidal achromatic and chromatic contrast variations. However, a Riemannian color difference metric, which includes the spatial and colorimetric properties of sinusoidal gratings, is lacking. Such a metric is important for various applications. Here we report on the development of a new Riemannian metric, for the prediction
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LMA fibers with increased higher-order mode loss for high average power, pulsed, diffraction-limited lasers Opt. Express (IF 3.8) Pub Date : 2024-04-22 Yaakov Glick, Jose Pincha, Ishu Kansal, Robert Windeler, Vasiliy Lukonin, Eric Monberg, Erin S. Lamb, Lalitkumar Bansal, and Jeffrey W. Nicholson
We demonstrate new, large-mode area (LMA) gain fibers with ∼25 µm mode-field diameter, and increased higher-order mode loss that enable diffraction limited, pulsed fiber lasers operating at high average power with high pulse energy. We achieved 1.6 mJ, ns pulses, with 1.2 kW average power and 370 kW peak power in one of the new Yb-doped gain fibers. In a second, higher absorption fiber, we demonstrate
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Scene-based dual domain non-uniformity correction algorithm for stripe and optics-caused fixed pattern noise removal Opt. Express (IF 3.8) Pub Date : 2024-04-22 Yuan Liu, Bingwen Qiu, Yayuan Tian, Juan Cai, Xiubao Sui, and Qian Chen
Non-uniformity is a long-standing problem that significantly degrades infrared images through fixed pattern noise (FPN). Existing scene-based algorithms for non-uniformity correction (NUC) effectively eliminate stripe FPN assuming consistent inter-frame non-uniformity. However, they are ineffective in handling spatially continuous optical FPN. In this paper, a scene-based dual domain correction approach
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Equalization of RGB coupling efficiencies of metasurface waveguide coupler by adjusting imaginary part of refractive index Opt. Express (IF 3.8) Pub Date : 2024-04-22 Ruqing Duan, Diyang Gu, Chenhui Liang, Lele Xia, Hang Chen, Yuan Chen, and Liu Yang
Optical metasurfaces offer high-efficiency and flexible wavefront shaping for near-eye displays, especially in wideband waveguide couplers accommodating RGB primary colors. By leveraging the resonance characteristics of sub-wavelength periodic nanostructures, metasurfaces surpass the limitations of traditional optics that rely on multiple components and mediums. In this study, we propose adjustment
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Noise correction in differential phase contrast for improving phase sensitivity Opt. Express (IF 3.8) Pub Date : 2024-04-22 Hu Liu, Jialin Liu, Wei Zhou, Baoteng Xu, Zengqi Yue, Daxi Xiong, and Xibin Yang
Differential phase contrast (DPC) imaging relies on computational analysis to extract quantitative phase information from phase gradient images. However, even modest noise level can introduce errors that propagate through the computational process, degrading the quality of the final phase result and further reducing phase sensitivity. Here, we introduce the noise-corrected DPC (ncDPC) to enhance phase
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Human activity recognition using a single-photon direct time-of-flight sensor Opt. Express (IF 3.8) Pub Date : 2024-04-22 Germán Mora-Martín, Stirling Scholes, Robert K. Henderson, Jonathan Leach, and Istvan Gyongy
Single-Photon Avalanche Diode (SPAD) direct Time-of-Flight (dToF) sensors provide depth imaging over long distances, enabling the detection of objects even in the absence of contrast in colour or texture. However, distant objects are represented by just a few pixels and are subject to noise from solar interference, limiting the applicability of existing computer vision techniques for high-level scene
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Sub-pixel target fine spatial feature extraction method based on aperture coding and micro-scanning imaging mechanism Opt. Express (IF 3.8) Pub Date : 2024-04-22 Chao Zhang, Ying yuan, Xiaorui Wang, Yang Ning, Yue Li, and Yangyang Li
The small imaging size of targets over long distances results in the loss of geometry and spatial features. Current methods are subject to sampling limitations and cannot accurately capture the spatial features of sub-pixel targets. This paper proposes a method to accurately locate and extract the fine spatial features of sub-pixel targets through aperture coding and micro-scanning imaging. First,
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Broadband silicon nitride integrated polarization rotators at 780 nm Opt. Express (IF 3.8) Pub Date : 2024-04-22 Marcel W. Pruessner, Kyle J. Walsh, Nathan F. Tyndall, Nicholas M. Fahrenkopf, Alin O. Antohe, and Todd H. Stievater
Polarization management, and in particular polarization rotation, is becoming increasingly important for photonic integrated circuits (PICs). While fiber-optic networks are generally polarization insensitive, the large aspect ratio of high-index-contrast PIC waveguides leads to a large polarization-dependent response of integrated components such as waveguides, optical cavities, couplers, etc. Although
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Relations between near-field enhancements and Purcell factors in hybrid nanostructures of plasmonic antennas and dielectric cavities Opt. Express (IF 3.8) Pub Date : 2024-04-22 Xu-Tao Tang, Lin Ma, Yue You, Xiao-Jing Du, Hua Qiu, Xi-Hua Guan, Jun He, and Zhong-Jian Yang
Strong near-field enhancements (NFEs) of nanophotonic structures are believed to be closely related to high Purcell factors (FP). Here, we theoretically show that the correlation is partially correct; the extinction cross section (σ) response is also critical in determining FP. The divergence between NFE and FP is especially pronounced in plasmonic-dielectric hybrid systems, where the plasmonic antenna
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Encoding independent wavefronts in a single metasurface for high-order optical vortex recognition Opt. Express (IF 3.8) Pub Date : 2024-04-22 Kai He, Tigang Ning, Jing Li, Jingjing Zheng, Li Pei, and Jianshuai Wang
The orbital angular momentum (OAM) of vortex beams has great potential in optical communications due to its communication confidentiality and low crosstalk. It is necessary to design a plausible OAM pattern recognition mechanism. Abandoning AI models that require large datasets, a single passive all-dielectric metasurface consisting of TiO2 nanopillars on a SiO2 substrate is used to recognize high-order
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Fiber Bragg gratings fabricated in fibers with different geometries by femtosecond laser written through the coating and their applications in strain sensing and fiber laser Opt. Express (IF 3.8) Pub Date : 2024-04-22 Yingjie Li, Tao Chen, Jinhai Si, Zenghui Sun, Ruidong Lv, Daqi Zhang, Bo Gao, and Xun Hou
Applications of the type-I fiber Bragg gratings (FBGs) written through the coating (TTC) in strain sensing and tunable distributed Bragg reflector (DBR) fiber lasers were demonstrated. We reported the principle of selecting the distance between the fiber and the phase mask when writing type-I TTC FBGs. Type-I TTC FBGs written in commercially available acrylate-coated fibers with various geometries
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Broadband nonlinear conversion and random quasi-phase-matching in transparent glass composite Opt. Express (IF 3.8) Pub Date : 2024-04-22 Jinwei Cao, Yipeng Lun, Xingzhao Huang, Siyun Li, Rongtai Lu, Meihui Zhang, Xu Lu, M. Sun, Huakang Yu, and Q. Qian
With the development of laser technology, nonlinear optics plays a crucial role in frequency conversion. However, the generation of second harmonics in nonlinear optical crystals is generally subject to rigorous phase-matching conditions that hinder the performance of broadband tunability. It is believed that introducing disorders in nonlinear optical materials is helpful to overcome this obstacle
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Nonlinear dynamics of an interband cascade laser with optical injection Opt. Express (IF 3.8) Pub Date : 2024-04-22 Kai-Li Lin, Peng-Lei Wang, Yi-Bo Peng, Yu Deng, and Cheng Wang
This work reports the nonlinear dynamics of a mid-infrared interband cascade laser (ICL) subject to optical injection. It is shown that the stable locking regime is asymmetric and broadens with increasing injection strength. Outside the locking regime, the ICL mostly produces period-one oscillations. However, three categories of periodic pulse oscillations are observed in the vicinity of the Hopf bifurcation
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Inelastic two-wave mixing induced high-efficiency transfer of optical vortices Opt. Express (IF 3.8) Pub Date : 2024-04-22 Xu Deng, Tao Shui, and Wen-Xing Yang
A scheme for high-efficiency transfer of optical vortices is proposed by an inelastic two-wave mixing (ITWM) process in an inverted-Y four-level atomic medium, which is originally prepared in a coherent superposition of two ground states. The orbital angular momentum (OAM) information in the incident vortex probe field can be transferred to the generated signal field through the ITWM process. Choosing
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Deep learning-assisted inverse design of nanoparticle-embedded radiative coolers Opt. Express (IF 3.8) Pub Date : 2024-04-18 Min Ju Kim, June Tae Kim, Mi Jin Hong, Sang Wook Park, and Gil Ju Lee
Radiative cooling is an energy-efficient technology without consuming power. Depending on their use, radiative coolers (RCs) can be designed to be either solar-transparent or solar-opaque, which requires complex spectral characteristics. Our research introduces a novel deep learning-based inverse design methodology for creating thin-film type RCs. Our deep learning algorithm determines the optimal
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Long-term monitoring chlorophyll-a concentration using HJ-1 A/B imagery and machine learning algorithms in typical lakes, a cold semi-arid region Opt. Express (IF 3.8) Pub Date : 2024-04-18 Jianhua Ren, Haoyun Zhou, Zui Tao, Liu Ge, Kaishan Song, Shiqi Xu, Yong Li, Lele Zhang, Xiyu Zhang, and Sijia Li
Chlorophyll a (Chl-a) in lakes serves as an effective marker for assessing algal biomass and the nutritional level of lakes, and its observation is feasible through remote sensing methods. HJ-1 (Huanjing-1) satellite, deployed in 2008, incorporates a CCD capable of a 30 m resolution and has a revisit interval of 2 days, rendering it a superb choice or supplemental sensor for monitoring trophic state
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Effect of turbulence-induced sediment resuspension and sedimentation on underwater wireless optical communication Opt. Express (IF 3.8) Pub Date : 2024-04-18 Hexiang Yuan, Meiwei Kong, Mengqi Wang, Wenxin Cui, Yanyan Pan, Hui Zhou, and Qunhui Yang
In real-life marine environments, the composition and grain size of suspended sediments and the resuspension and sedimentation of sediments caused by turbulence may have a significant impact on underwater wireless optical communication (UWOC). However, to date, researchers have not conducted quantitative research on this issue. To this end, we innovatively study the effects of different compositions
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Enhanced imaging with binary circular Dammann Fresnel zone plate Opt. Express (IF 3.8) Pub Date : 2024-04-18 Stefan R. Anton, Nadav Shabairou, Stefan G. Stanciu, George A. Stanciu, and Zeev Zalevsky
We introduce a novel approach in optical engineering by combining Dammann gratings with binary Fresnel zone plates to create a unique hybrid optical element with enhanced energetic efficiency of its focal spots. Traditionally, binary Fresnel zone plates focus light at multiple points with varying intensities, while Dammann gratings are renowned for their efficient and uniform light splitting capabilities
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Optical spatial differentiation enabled layer sensing of two-dimensional atomic crystals Opt. Express (IF 3.8) Pub Date : 2024-04-19 Jin Zhang, Hanqing Wu, Mian Huang, Xin Dai, Tao Zhang, Yingdan Li, and Xiaoyan Yu
Zero-thickness model and slab model are two important models in the description of optical behaviors in two-dimensional atomic crystals. The predicted difference in optical behaviors between the two models is very small, which is difficult to distinguish by established measurement methods. Here, we present an optical spatial differentiation method to examine the difference in edge images of different
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Surrogate gradient learning in spiking networks trained on event-based cytometry dataset Opt. Express (IF 3.8) Pub Date : 2024-04-18 Muhammed Gouda, Steven Abreu, and Peter Bienstman
Spiking neural networks (SNNs) are bio-inspired neural networks that - to an extent - mimic the workings of our brains. In a similar fashion, event-based vision sensors try to replicate a biological eye as closely as possible. In this work, we integrate both technologies for the purpose of classifying micro-particles in the context of label-free flow cytometry. We follow up on our previous work in
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Unsupervised reconstruction with a registered time-unsheared image constraint for compressed ultrafast photography Opt. Express (IF 3.8) Pub Date : 2024-04-18 Haoyu Zhou, Yan Song, Zhiming Yao, Dongwei Hei, Yang Li, Baojun Duan, Yinong Liu, and Liang Sheng
Compressed ultrafast photography (CUP) is a computational imaging technology capable of capturing transient scenes in picosecond scale with a sequence depth of hundreds of frames. Since the inverse problem of CUP is an ill-posed problem, it is challenging to further improve the reconstruction quality under the condition of high noise level and compression ratio. In addition, there are many articles
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Programmable photoacoustic manipulation of microparticles in liquid Opt. Express (IF 3.8) Pub Date : 2024-04-18 Jinzhi Li, Xichuan Zhao, Ruoqin Zhang, Di Zhou, Feng Li, Zhiyuan Li, and Honglian Guo
Particle manipulation through the transfer of light or sound momentum has emerged as a powerful technique with immense potential in various fields, including cell biology, microparticle assembly, and lab-on-chip technology. Here, we present a novel method called Programmable Photoacoustic Manipulation (PPAM) of microparticles in liquid, which enables rapid and precise arrangement and controllable transport