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Multiplication-free and hardware-efficient baud-rate timing error detector for Nyquist and faster than Nyquist optical IM/DD systems Opt. Lett. (IF 3.1) Pub Date : 2024-04-24 Jianwei Tang, Jinlong Wei, Junpeng Liang, Zhaopeng Xu, Tianfeng Zhao, Chen Cheng, Yaguang Hao, Bang Yang, Zhongliang Sun, Ke Li, Yunchen Li, Lingjun Zhou, Zhixue He, Yanfu Yang, and Weisheng Hu
Clock recovery (CR) algorithms that support higher baud rates and advanced modulation formats are crucial for short-distance optical interconnections, and it is desirable to push CR to operate at baud rate with minimal computing resources and power. In this Letter, we proposed a hardware-efficient and multiplication operation-free baud-rate timing error detector (TED) as a solution to meet these demands
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Photonic-assisted high-order vector millimeter-wave signal generation enabled by DSM Opt. Lett. (IF 3.1) Pub Date : 2024-04-24 Acai Tan, Yanyi Wang, Zhengxuan Li, Yingxiong Song, and Jianjun Yu
We propose an optical dual-single-sideband (dual-SSB) modulated 16384-quadrature amplitude modulation (QAM) photonic vector millimeter-wave (mm-wave) signal generation scheme based on delta-sigma modulation (DSM). With the aid of the DSM, the severe nonlinear distortion of envelope detection for high-order QAM modulation signals in wireless communication can be effectively resolved. For the validation
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Overcoming oxygen inhibition in UV photolithography for the fabrication of low-loss polymer waveguides Opt. Lett. (IF 3.1) Pub Date : 2024-04-24 Xingyu Xu, Xiao Lu, Fufei Pang, Na Chen, Heming Wei, Liang Zhang, Qianwu Zhang, and Tingyun Wang
Perfluorinated acrylate polymer materials exhibit low absorption loss at 1310 and 1550 nm, but molecular oxygen inhibits their photocuring. We propose a novel, to our knowledge, UV photolithography method incorporating a pre-exposure process for fabricating low-loss perfluorinated acrylate polymer waveguides. During the pre-exposure process, a partially cured thin layer forms on the core layer, effectively
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Improved power and temperature performance of half-disk diode microlasers Opt. Lett. (IF 3.1) Pub Date : 2024-04-24 Fedor Zubov, Artem Beckman, Yuri Shernyakov, Nikolay Kaluzhnyy, Sergey Mintairov, Yulia Guseva, Marina Kulagina, Vladimir G. Dubrovskii, and Mikhail Maximov
The power and temperature characteristics of Ø200 µm half-disk microlasers with a half-ring metal contact and high-density InGaAs/GaAs quantum dots are studied. In a continuous wave (CW) mode, the maximal optical power at 20°C was 134 mW, and the maximal CW lasing temperature reached 113°C. In a pulsed regime the maximal optical power of 1.6 W, limited by catastrophic degradation, was achieved. By
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High-average-power single-frequency pulse optical parametric oscillator based on pulse-integrated seed-injection automatic locking Opt. Lett. (IF 3.1) Pub Date : 2024-04-24 Jiaqi Song, Jiliang Qin, Xuechen Cao, Donglin Cheng, Yanan Chen, and Huadong Lu
Near-infrared nanosecond (ns) single-longitudinal-mode (SLM) pulse light generated from an optical parametric oscillator (OPO) is an important source in nonlinear optics and high-precision spectral analysis. In this Letter, a stable SLM near-infrared ns pulse light source generated from the OPO is presented, which is achieved by developing a seed-injection automatic locking technique based on a pulse-integrated
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Reciprocal polarization imaging of optical activity in reflection Opt. Lett. (IF 3.1) Pub Date : 2024-04-24 Zhineng Xie, Mengjiao Zhu, Weihao Lin, Guowu Huang, Yifan Ge, Yansen Hu, Xin Jin, and Min Xu
We present reciprocal polarization imaging for the optical activity of chiral media in reflection geometry. The method is based on the reciprocal polar decomposition of backscattering Mueller matrices accounting for the reciprocity of light waves in forward and backward scattering paths. Anisotropic depolarization is introduced to gain sensitivity to optical activity in backscattering. Experiments
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High performance polarizer on thin-film lithium niobate with width-tapered Euler bending Opt. Lett. (IF 3.1) Pub Date : 2024-04-23 Weixi Liu, Chengfeng Wen, Chenkun Lei, Lijia Song, Daoxin Dai, and Yaocheng Shi
In this Letter, we propose and demonstrate an integrated polarizer on thin film lithium niobate (TFLN). The polarizer consists of a width-tapered 180° Euler bending waveguide featuring thin thickness and bilevel mode convertors with silica cladding. Notably, the TE0 mode is efficiently confined in the waveguide, while the TM0 mode confronts significant bending losses. The measurements reveal that the
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Programmable spin and transport of a living shrimp egg through photoacoustic pressure Opt. Lett. (IF 3.1) Pub Date : 2024-04-23 Xichuan Zhao, Ruoqin Zhang, Jinzhi Li, Di Zhou, Feng Li, and Honglian Guo
In the fields of biomedicine and microfluidics, the non-contact capture, manipulation, and spin of micro-particles hold great importance. In this study, we propose a programmable non-contact manipulation technique that utilizes photoacoustic effect to spin and transport living shrimp eggs. By directing a modulated pulsed laser toward a liquid-covered stainless-steel membrane, we can excite patterned
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High-Q two-dimensional photonic crystal nanocavity on glass with an upper glass thin film Opt. Lett. (IF 3.1) Pub Date : 2024-04-23 Ryusei Kawata, Akinari Fujita, Natthajuks Pholsen, Satoshi Iwamoto, and Yasutomo Ota
We numerically analyze two-dimensional photonic crystal (PhC) nanocavities on glass with a thin glass film on top of the structure. We investigated a multistep heterostructure GaAs PhC nanocavity located on glass. We found that covering the structure even with a very thin glass film efficiently suppresses unwanted polarization mode conversion occurring due to the asymmetric refractive index environment
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Widely tunable S-band ring-cavity Tm3+-doped fluorotellurite fiber laser Opt. Lett. (IF 3.1) Pub Date : 2024-04-22 Linghao Cui, Zhixu Jia, Junjie Wang, Chuanze Zhang, Feng Tian, Fanchao Meng, Yasutake Ohishi, Weiping Qin, and Guanshi Qin
Tm3+-doped fluorotellurite fibers (TDFTFs) are fabricated by using a rod-in-tube method. A 2.1 m long TDFTF is used as the gain medium, in which both ends of the TDFTF are connected to a short piece of a silica fiber by direct fusion splicing. By inserting the above TDFTF and a tunable optical bandpass filter into a ring cavity and employing a 1400/1570 nm dual-wavelength pumping technique, tunable
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Active feedback stabilization of super-efficient microcombs in photonic molecules Opt. Lett. (IF 3.1) Pub Date : 2024-04-22 Israel Rebolledo-Salgado, Óskar B. Helgason, Vicente Durán, Marcello Girardi, Martin Zelan, and Victor Torres-Company
Dissipative Kerr soliton (DKS) frequency combs, when generated within coupled cavities, exhibit exceptional performance concerning controlled initiation and power conversion efficiency. Nevertheless, to fully exploit these enhanced capabilities, it is necessary to maintain the frequency comb in a low-noise state over an extended duration. In this study, we demonstrate the control and stabilization
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Hyperspectral microscopy of boron nitride nanolayers using hybrid femto/picosecond coherent anti-Stokes Raman scattering Opt. Lett. (IF 3.1) Pub Date : 2024-04-22 Elodie Lin, Michael Scherman, Aurelie Pierret, Brigitte Attal-Tretout, Amandine Andrieux, Laure Tailpied, Takashi Taniguchi, Kenji Watanabe, and Annick Loiseau
The rise in interest in two-dimensional (2D) nanomaterials has been notable in recent years. In particular, hexagonal boron nitride (h-BN), recognized as an optimal substrate for enhancing graphene properties, holds promise for electronic applications. However, the widely employed spontaneous Raman microscopy, a gold standard for graphene study, faces strong limitations in h-BN due to its large bandgap
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Symbol-level fiber-longitudinal power profile estimation Opt. Lett. (IF 3.1) Pub Date : 2024-04-19 Yingjie Jiang, Du Tang, Zhengkang Wang, Ji Luo, Bofang Zheng, and Yaojun Qiao
Symbol-level fiber-longitudinal power profile estimation (PPE) greatly reduces the implementation complexity compared with the waveform-level PPE using oversampled data. However, symbol-rate data cannot account for the inter-sample interaction, which leads to inaccuracy of the absolute power estimation. To realize an accurate symbol-level PPE, we provide an in-depth analysis of the differences between
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Blind frequency offset estimation method based on a minimum phase correction error for a full spectrum modulated NFDM system Opt. Lett. (IF 3.1) Pub Date : 2024-04-19 Jianqing He, Jianping Li, Yuwen Qin, Xinkuo Yu, Tao Huang, Gai Zhou, and Songnian Fu
To improve the spectral efficiency of a full spectrum modulated nonlinear frequency division multiplexing (FS-NFDM) system, a blind frequency offset estimation (FOE) method has been proposed. The approach based on the minimum phase correction error can achieve high estimation accuracy of sub-MHz without need of any training symbols. Furthermore, in order to reduce the computational complexity, an eigenvalue-shift
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Crackless high-aspect-ratio processing of a silica glass with a temporally shaped ultrafast laser Opt. Lett. (IF 3.1) Pub Date : 2024-04-19 Guoqi Ren, Huijie Sun, Keiichi Nakagawa, Naohiko Sugita, and Yusuke Ito
In this Letter, we propose a crackless high-aspect-ratio processing method based on a temporally shaped ultrafast laser. The laser pulse is temporally split into two sub pulses: one with smaller energy is used to excite electrons but without ablation so that the applied pressure to the sample is weak, and the other one is used to heat the electrons and achieve material removal after it is temporally
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Bidirectional Raman soliton-like combs with unidirectional pump in a spherical microresonator Opt. Lett. (IF 3.1) Pub Date : 2024-04-19 Alexey V. Andrianov and Elena A. Anashkina
We experimentally demonstrate bidirectional Raman soliton-like combs in a whispering gallery mode microresonator with a unidirectional pump for the first time, to the best of our knowledge. We develop a relatively simple theoretical model and find an analytical solution for forward- and backward-propagating Raman sech2-shaped solitons in an anomalous dispersion region under unidirectional pumping in
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Deep-ultraviolet n-ZnGa2O4/p-GaN heterojunction photodetector fabricated by pulsed laser deposition Opt. Lett. (IF 3.1) Pub Date : 2024-04-19 Ning Cao, Lichun Zhang, Xin Li, Xianling Meng, Doudou Liang, Yadan Zhu, and Fengzhou Zhao
Zinc gallium oxide (ZnGa2O4) has attracted considerable interest in deep-ultraviolet photodetectors, due to the ultrawide bandgap, high transmittance in the ultraviolet (UV) region, and excellent environmental stability. In this study, ZnGa2O4 thin films were deposited on p-GaN epi-layers using pulsed laser deposition, resulting in improved crystalline quality. The ZnGa2O4 film exhibited a bandgap
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Multi-grayscale driving system for passive-matrix alternating current electroluminescence display Opt. Lett. (IF 3.1) Pub Date : 2024-04-19 Qitian Fan, Jintao Shi, Simu Zhu, Bo-ru Yang, and Shaozhi Deng
Alternating current electroluminescence (ACEL) has great potential in flexible displays, especially in textile displays. However, since ACEL needs high-frequency, high-voltage AC signal to drive, there remains no driving scheme for pixelated ACEL display to achieve multiple gray scales. In this work, a driving scheme based on full-bridge inverters is proposed for passive-matrix ACEL (PMACEL) display
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Low-loss and compact photonic lantern based on a step-index double cladding fiber Opt. Lett. (IF 3.1) Pub Date : 2024-04-18 Cong Zhang, Yue Wang, Senyu Zhang, Meng Xiang, Songnian Fu, and Yuwen Qin
The fulfilment of the adiabatic criterion is indispensable for the realization of a low-loss photonic lantern (PL), concurrently imposing a stringent restriction on the taper transition length of the PL. Here, by relaxing the adiabatic criterion, a low-loss and compact PL based on a step-index double cladding fiber (SI-DCF) is theoretically proposed and experimentally demonstrated. The use of SI-DCF
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High-order QAM NANF transmission utilizing MIMO equalizer integrated with low-complexity decision-directed carrier phase estimation Opt. Lett. (IF 3.1) Pub Date : 2024-04-18 Chen Wang, Kaihui Wang, Jianyu Long, Wen Zhou, Feng Zhao, Lei Shen, Peng Li, and Jianjun Yu
We experimentally realized a high-speed nested anti-resonant nodeless fiber (NANF) transmission with the assistance of the polarization division multiplexing (PDM) and probabilistic shaping (PS) technology. In this system, a low-complexity multiple-input multiple-output (MIMO) real-valued equalizer (RVE) is integrated with decision-directed carrier phase estimation (DDCPE), which is robust against
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Optical fiber bundle differential compressive imaging Opt. Lett. (IF 3.1) Pub Date : 2024-04-18 Zhixiang Jiang, Ya Wen, Lipei Song, Da Li, and Xing Zhao
We present a differential compressive imaging method for an optical fiber bundle (OFB), which provides a solution for an ultrathin bend-resistant endoscope with high resolution. This method uses an OFB and a diffuser to generate speckle illumination patterns. Differential operation is additionally applied to the speckle patterns to produce sensing matrices, by which the correlation between the matrices
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Experimental reservoir computing with diffractively coupled VCSELs Opt. Lett. (IF 3.1) Pub Date : 2024-04-18 Moritz Pflüger, Daniel Brunner, Tobias Heuser, James A. Lott, Stephan Reitzenstein, and Ingo Fischer
We present experiments on reservoir computing (RC) using a network of vertical-cavity surface-emitting lasers (VCSELs) that we diffractively couple via an external cavity. Our optical reservoir computer consists of 24 physical VCSEL nodes. We evaluate the system’s memory and solve the 2-bit XOR task and the 3-bit header recognition (HR) task with bit error ratios (BERs) below 1% and the 2-bit digital-to-analog
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Multi-toric optical element to compensate ocular astigmatism with increased tolerance under rotation Opt. Lett. (IF 3.1) Pub Date : 2024-04-17 Diana Gargallo, Anabel Martinez-Espert, Sara Perches, M. Victoria Collados, Laura Remón Martín, and Jorge Ares
A new, to the best of our knowledge, optical element designed to compensate regular astigmatism while exhibiting increased tolerance to rotational misalignment is introduced. The element incorporates an optical design based on concentric annular regions with slightly different cylindrical axis angular positions. To assess visual quality performance as a function of rotation, retinal image simulation
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Polarization feature fusion and calculation of birefringence dynamics in complex anisotropic media Opt. Lett. (IF 3.1) Pub Date : 2024-04-18 Rui Hao, Nan Zeng, Zheng Zhang, Honghui He, Chao He, and Hui Ma
As a complex anisotropic medium, variation in birefringence within biological tissues is closely associated with numerous physiological behaviors and phenomena. In this Letter, we propose a polarization feature fusion method and corresponding polarimetric parameters, which exhibit excellent performance of capturing the birefringence dynamic variation process in complex anisotropic media. By employing
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Long range topography by dispersion unmatched spectral-domain interferometry based on virtually imaged phased array modes Opt. Lett. (IF 3.1) Pub Date : 2024-04-18 Tao Han, Lu Yang, Yun Tang, Changyong Chen, Cui Ma, Zhiyi Liu, and Zhihua Ding
We propose to realize a long range topography by dispersion unmatched spectral-domain interferometry based on virtually imaged phased array (VIPA) modes. By filtering the continuous spectrum of a supercontinuum source through a side-entrance Fabry–Perot etalon configured at two input angles, two groups of VIPA modes are generated. A method based on unmatched dispersion is proposed for non-aliasing
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Can linear pre-emphasis mitigate the nonlinear distortion of light-emitting diodes? Opt. Lett. (IF 3.1) Pub Date : 2024-04-17 Juliusz Bojarczuk, Michal Marzecki, and Grzegorz Stepniak
Transmitter pre-emphasis is one of the techniques proposed to improve the relatively poor frequency responses of light-emitting diodes (LEDs) used in visible light communications (VLC) as light sources. However, according to the communications theory in linear channels, pre-emphasis may only be as good as the not particularly efficient feed-forward equalizer (FFE). Given the increase in peak-to-average
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High-sensitivity optical tomography of instabilities in supersonic gas flow Opt. Lett. (IF 3.1) Pub Date : 2024-04-17 Marek Raclavský, Kavya H. Rao, Uddhab Chaulagain, Marcel Lamač, and Jaroslav Nejdl
Characterization of gas targets relies largely on conventional optical techniques, providing millisecond time resolution, which not only overlooks the fluctuations occurring at shorter time scales but also often challenges the sensitivity limits of optical probing as their refractive index is close to unity. Hence, the ability to resolve these fluctuations needs to be addressed as it is paramount for
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Auxiliary-cavity-enhanced quantum estimation of optorotational-coupling strength Opt. Lett. (IF 3.1) Pub Date : 2024-04-17 Jia-Xin Peng, Zeng-Xing Liu, Muhammad Asjad, and Naeem Akhtar
A scheme is proposed to achieve significantly enhanced quantum estimation of optorotational-coupling (ORC) strength by coupling a driven auxiliary cavity to a Laguerre–Gaussian (L–G) rotational cavity, where the ORC originates from the exchange of orbital angular momentum between a L–G light and rotational mirror. The results indicate that, by appropriately designing the auxiliary-cavity mechanism
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GaN integrated optical devices for glycerol viscosity measurement Opt. Lett. (IF 3.1) Pub Date : 2024-04-17 Yumeng Luo, Binlu Yu, Hongyu Yu, and Kwai Hei Li
This Letter presents the fabrication and characterization of a chip-scale GaN optical device for measuring glycerol viscosity. The monolithically integrated GaN chip with a size of 1 × 1 mm2 comprises a light-emitting diode (LED) and a photodiode (PD) on a transparent sapphire substrate. The glycerol droplet applied to the device acts as a medium for coupling light from the LED to the PD. When a mechanical
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Microwave re-excitation of femtosecond laser tagging for highly flexible velocimetry Opt. Lett. (IF 3.1) Pub Date : 2024-04-17 Fynn Reinbacher, Sarang Bidwai, and James B. Michael
Molecular tagging velocimetry is typically species specific and limited by excited state/species lifetimes. We utilize laser-generated ionization, long-lived anions, and a time-delayed microwave pulse to monitor the tagged region up to several milliseconds. This non-resonant excitation and microwave interaction is demonstrated in a range of gas mixtures. Signal levels show up to 1000-fold improvement
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Efficient single-cycle mid-infrared femtosecond laser pulse generation by spectrally temporally cascaded optical parametric amplification with pump energy recycling Opt. Lett. (IF 3.1) Pub Date : 2024-04-17 Hao Yuan, Pei Huang, Tongyu Feng, Yahui Ma, Xianglin Wang, Huabao Cao, Yishan Wang, Wei Zhao, and Yuxi Fu
We proposed spectrally temporally cascaded optical parametric amplification (STOPA) using pump energy recycling to simultaneously increase spectral bandwidth and conversion efficiency in optical parametric amplification (OPA). Using BiB3O6 and KTiOAsO4 nonlinear crystals, near-single-cycle mid-infrared (MIR) pulses with maximum energy conversion efficiencies exceeding 25% were obtained in simulations
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Intense emission at 605 nm from Pr3+-doped fluorotellurite glass fibers Opt. Lett. (IF 3.1) Pub Date : 2024-04-16 Jinming Yan, Zhixu Jia, Junjie Wang, Chuanze Zhang, Fangning Wang, Fanchao Meng, Yasutake Ohishi, Daming Zhang, Weiping Qin, Fei Wang, and Guanshi Qin
Pr3+-doped fluorotellurite glass fibers (PDFTFs) were fabricated by using a rod-in-tube method. By using a 976/1400 nm dual-wavelength upconversion pump technique, an intense emission at 605 nm was obtained from a 6 cm long PDFTF, which was attributed to the transition 1D2 → 3H4 of Pr3+ ions. With an increase in power of the 1400 nm laser from ∼34 to ∼136 mW, the spectral bandwidth of the 605 nm emission
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Influence of static and dynamic ocular aberrations on full-field optical coherence tomography for in vivo high-resolution retinal imaging Opt. Lett. (IF 3.1) Pub Date : 2024-04-16 Yao Cai, Olivier Thouvenin, Kate Grieve, and Pedro Mecê
Under spatially incoherent illumination, time-domain full-field optical coherence tomography (FFOCT) offers the possibility to achieve in vivo retinal imaging at cellular resolution over a wide field of view. Such performance is possible, albeit there is the presence of ocular aberrations even without the use of classical adaptive optics. While the effect of aberrations in FFOCT has been debated these
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Optical wireless communication using a flexible and waterproof perovskite color converter Opt. Lett. (IF 3.1) Pub Date : 2024-04-16 Feifei Qin, Feng Chen, Yue Cao, Linning Wang, Chengwei Wang, Yanan Liao, Yuhang Dai, Junfeng Lu, Xinru Lan, Xu Wang, XianWu Tang, Xiaoyan Liu, Gangyi Zhu, and Yongjin Wang
In this Letter, the CH3NH3PbBr3 nanocrystals (NCs) are embedded into the interstices of the fluorine (polyvinyl fluoride/polyvinylidene fluoride, PVF/PVDF) matrix on polyethylene terephthalate (PET) substrate to introduce new advantages, such as being flexible and waterproof, while maintaining the high optical performance of perovskites. The sample’s photoluminescence (PL) spectra under 325 nm laser
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Mn2+/Mg2+ co-doped AlON ceramic with ultra-narrowband green emission combining high transparency toward a wide gamut backlight application Opt. Lett. (IF 3.1) Pub Date : 2024-04-16 Xiaolan Zhou, Shengyuan Chen, Cong Zhang, Xu Huang, Kailei Lu, Jianqi Qi, and Tiecheng Lu
Narrowband green-emission, combined with superior physicochemical stability and thermal performance, is regarded as a common pursuit in backlight display applications. However, mainstream phosphor-converted materials composed of resin or silicone resin easily encounter the dilemma of thermal decomposition and chemical corrosion for practical use. To overcome this problem, in this work, Mn2+/Mg2+ co-doped
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Multi-channel delay sampling to extend imaging depth in high-speed swept-source OCT systems Opt. Lett. (IF 3.1) Pub Date : 2024-04-16 Yaping Shi, Jian Liu, Zhaoyu Gong, Christopher Burger, Vijaysekhar Jayaraman, and Ruikang K. Wang
We present a multi-channel delay sampling method to extend imaging depth in high-speed swept-source optical coherence tomography (SS-OCT). A balanced detector captures interference signals, converting them into electrical signals, which are then split into N channels, each with fixed time delays determined by the length of electrical cables. Then, they are digitized by an N-channel acquisition card
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Untrained neural network enabling fast and universal structured-illumination microscopy Opt. Lett. (IF 3.1) Pub Date : 2024-04-16 Zitong Ye, Xiaoyan Li, Yile Sun, Yuran Huang, Xu Liu, Yubing Han, and Cuifang Kuang
Structured-illumination microscopy (SIM) offers a twofold resolution enhancement beyond the optical diffraction limit. At present, SIM requires several raw structured-illumination (SI) frames to reconstruct a super-resolution (SR) image, especially the time-consuming reconstruction of speckle SIM, which requires hundreds of SI frames. Considering this, we herein propose an untrained structured-illumination
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Broadband long-wavelength upconversion in ultra-short nonlinear crystals Opt. Lett. (IF 3.1) Pub Date : 2024-04-16 Peter Tidemand-Lichtenberg and Christian Pedersen
Since the inception of the second-order nonlinear frequency conversion in 1961, enhancing the inherent low conversion efficiency has been a primary objective. This goal has been successfully accomplished through the utilization of cm-long nonlinear crystals characterized by high quality and nonlinearity, coupled with versatile phase-matching strategies and high-power mixing lasers. However, the reliance
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Quickly tunable ultra-narrow filter via a metal film waveguide Opt. Lett. (IF 3.1) Pub Date : 2024-04-16 Hongrui Shan, Qiheng Wei, Hailang Dai, and Xianfeng Chen
The development of fast, efficient, and cost-effective tunable optical filters is a tireless pursuit of the goal in the field of optical signal processing and communications. However, the traditional filters have been limited by their complex structures, slow tuning speed, and high cost. To address this challenge, we present a tunable ultra-narrow bandpass filter, which is fabricated by a metal layer
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Switchable hybrid-order optical vortex lattice Opt. Lett. (IF 3.1) Pub Date : 2024-04-16 Xueyun Qin, Hao Zhang, Miaomiao Tang, Yujie Zhou, Yuping Tai, and Xinzhong Li
Optical vortex (OV) modulation is a powerful technique for enhancing the intrinsic degrees-of-freedom in structured light applications. Particularly, the lattices involving multiple OVs have garnered significant academic interest owing to their wide applicability in optical tweezers and condensed matter physics. However, all OVs in a lattice possess the same order, which cannot be modulated individually
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Terahertz metalens for generating multi-polarized focal points and images with uniform intensity distributions Opt. Lett. (IF 3.1) Pub Date : 2024-04-16 Binbin Lu, Yefei Fu, Teng Zhang, Zuanming Jin, Xiaofei Zang, and Yiming Zhu
Metasurfaces have provided a flexible platform for designing ultracompact metalenses with unusual functionalities. However, traditional multi-foci metalenses are limited to generating circularly polarized (CP) or linearly polarized (LP) focal points, and the intensity distributions are always inhomogeneous/chaotical between the multiple focal points. Here, an inverse design approach is proposed to
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Structural and optical performance of NiV/Ti multilayer mirrors for Z-pinch plasma diagnostic at the wavelength region of 350–450 eV Opt. Lett. (IF 3.1) Pub Date : 2024-04-16 Zile Wang, Zhe Zhang, Jialian He, Angelo Giglia, Qiya Zhang, Runze Qi, Qiushi Huang, Shengzhen Yi, Zhong Zhang, and Zhanshan Wang
This Letter reports on investigations of novel, to the best of our knowledge, NiV(Ni93V7)/Ti multilayer mirrors for the operation in the wavelength region of 350–450 eV. Such mirrors are promising optical components for the Z-pinch plasma diagnostic. The NiV/Ti multilayers show superior structural and optical performance compared to conventional Ni/Ti multilayers. Replacing Ni with NiV in multilayers
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Learning-enabled data transmission with up to 32 multiplexed orbital angular momentum channels through a commercial multi-mode fiber Opt. Lett. (IF 3.1) Pub Date : 2024-04-15 Jihong Tang, Yaling Yin, Jingwen Zhou, Yong Xia, and Jianping Yin
Multiplexing orbital angular momentum (OAM) modes enable high-capacity optical communication. However, the highly similar speckle patterns of adjacent OAM modes produced by strong mode coupling in common fibers prevent the utility of OAM channel demultiplexing. In this paper, we propose a machine learning-supported fractional OAM-multiplexed data transmission system to sort highly scattered data from
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Modulated-symbol domain matched filtering scheme for photonic-assisted integrated sensing and communication system based on a single OFDM waveform Opt. Lett. (IF 3.1) Pub Date : 2024-04-12 Lede Yin and Jing He
In this Letter, a modulated-symbol domain matched filtering scheme based on orthogonal frequency division multiplexing (OFDM) is proposed for the photonic-assisted W-band integrated sensing and communication (ISAC) system. The photonic-assisted ISAC system based on a single OFDM waveform is experimentally demonstrated. By using the single OFDM waveform, it can improve the spectrum efficiency and achieve
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Optimized adaptation algorithms for low-complexity adaptive equalizers Opt. Lett. (IF 3.1) Pub Date : 2024-04-12 Shuo Zheng, Min Yang, Guofeng Yan, Yanjun Zhu, Hua Zhang, Chaonan Yao, Yuchen Shao, and Jian Wang
In order to address the high-power consummation issue of conventional multi-input and multi-output (MIMO) adaptive equalizer (AEQ) for short-reach coherent transmissions, several state-of-the-art low-complexity AEQs have been proposed. In our work, optimized adaptation algorithms for low-complexity real-valued (RV) AEQs with different structures are analyzed. Moreover, an approach to avoid introducing
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Optical phase encoding in a pulsed approach to reservoir computing Opt. Lett. (IF 3.1) Pub Date : 2024-04-11 Johan Henaff, Matthieu Ansquer, Miguel C. Soriano, Roberta Zambrini, Nicolas Treps, and Valentina Parigi
The exploitation of the full structure of multimode light fields enables compelling capabilities in many fields including classical and quantum information science. We exploit data-encoding on the optical phase of the pulses of a femtosecond laser source for a photonic implementation of a reservoir computing protocol. Rather than intensity detection, data-reading is done via homodyne detection that
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Visible light positioning system using a smartphone’s built-in ambient light sensor and inertial measurement unit Opt. Lett. (IF 3.1) Pub Date : 2024-04-11 Yuan Zhuang, Yaxin Wang, Xiansheng Yang, and Tianbing Ma
In recent years, the visible light positioning field has experienced remarkable advancements. However, smartphones find it difficult to identify light-emitting diode (LED) and extract each LED’s light signal intensity due to the low-frequency and uneven sampling of built-in ambient light sensors (ALS, which is a photodiode that measures ambient light in lux units). Thus, traditional visible light positioning
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Determining triple half-twist of optical Möbius strips in electromagnetic fields with a non-planar structure Opt. Lett. (IF 3.1) Pub Date : 2024-04-11 K. S. Grigoriev and V. A. Makarov
Polarization ellipses in a nonparaxial field form twisted strips when traced along closed contours around a circular polarization singularity line. We found an analytical expression for the twist number of the strip when the contour is coplanar with the polarization ellipse in its center. Necessary and sufficient conditions for strips having one or three half-twists are found. A set of five parameters
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Imaging focused laser differential interferometry Opt. Lett. (IF 3.1) Pub Date : 2024-04-11 Andrew W. Marsh, Alice N. Kramer, Kevin N. Maranto, and Yi Chen Mazumdar
Focused laser differential interferometry (FLDI) is an important diagnostic for measuring density fluctuations in high-speed flows. Currently, however, high dynamic range FLDI is limited to photodiode measurements. In order to spatially resolve multiple locations within complex flows, we present a novel, to the best of our knowledge, refractive-optic imaging FLDI concept that not only produces two-dimensional
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Efficient and high-speed coupling modulation of silicon racetrack ring resonators at 2 µm waveband Opt. Lett. (IF 3.1) Pub Date : 2024-04-12 Xi Wang, Jianing Wang, Yong Yao, Shumin Xiao, Qinghai Song, and Ke Xu
Significantly increased interests have been witnessed for the 2 µm waveband which is considered to be a promising alternative window for fiber and free-space optical communications. However, the less mature device technology at this wavelength range is one of the primary obstacles toward practical applications. In this work, we demonstrate an efficient and high-speed silicon modulator based on carrier
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Integrated segmented IQ-modulator for orthogonal sampling and multi-level high-bandwidth signal generation Opt. Lett. (IF 3.1) Pub Date : 2024-04-15 Younus Mandalawi, Mohamed I. Hosni, Janosch Meier, Karanveer Singh, Souvaraj De, Ranjan Das, and Thomas Schneider
Photonic-assisted signal processing of high-bandwidth signals emerges as a solution for challenges encountered in electronic-based processing. Here we present a concept for a compact, photonic-assisted digital-to-analog converter (DAC) and optical IQ-modulator in one single integrated device based on two innovative concepts: a segmented Mach–Zehnder modulator and orthogonal sampling. For electrically
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Wavelength extension beyond 3 µm in a Ho3+/Pr3+ co-doped AlF3-based fiber laser Opt. Lett. (IF 3.1) Pub Date : 2024-04-11 Niannian Xu, Pengfei Wang, Shunbin Wang, Mo Liu, Juan Wang, Zhenrui Li, and Zhiyong Yang
In this Letter, we report continuous-wave (CW) lasers with wavelengths beyond 3 µm in homemade Ho3+/Pr3+ co-doped AlF3-based glass fibers. The laser cavity was established through the integration of a dichroic mirror (DM, HR@3–3.1 µm) positioned at the pump end and a partial reflectivity (PR) fiber Bragg grating (FBG) situated at the laser emission end. The FBGs in AlF3-based glass fibers were fabricated
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Tunable and mode-locked Tm,Ho:GdScO3 laser Opt. Lett. (IF 3.1) Pub Date : 2024-04-12 Jian Liu, Ning Zhang, Qingsong Song, Heng Ding, Yinyin Wang, Peng Chen, Zebin Wang, Yanyan Xue, Jie Xu, Yongguang Zhao, Xiaodong Xu, Kheiredding Lebbou, and Jun Xu
A novel, to the best of our knowledge, Tm,Ho:GdScO3 crystal grown using the Czochralski method was investigated for its polarized spectroscopic properties and laser performance in both tunable continuous-wave (CW) and mode-locked regimes. The crystal’s multisite structure (Gd3+/Sc3+ site) and Tm3+/Ho3+ dopants contributed to spectral broadening, enabling a tunable laser operation from 1914 to 2125
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Yb-doped mode-locked fiber laser with a hybrid structure of NPR and a Lyot filter as the saturable absorber Opt. Lett. (IF 3.1) Pub Date : 2024-04-12 Yongjie Pu, Pan Guo, Yuan Gao, Qihao Shen, Zhicheng Zhang, Minyu Fan, and Sha Wang
Passively mode-locked fiber lasers based on a nonlinear polarization rotation (NPR) have attracted much attention due to their ability to generate short pulses with wide spectra and high peak power. However, environmental perturbations can easily cause the lasers to lose the mode-locked state and make it a challenge for practical application. The aim of this research is to improve the laser stability
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High-energy, low-jitter, narrowband ps probe laser for kHz-rate fs/ps coherent anti-Stokes Raman scattering Opt. Lett. (IF 3.1) Pub Date : 2024-04-12 Erik L. Braun, Karna Patel, Venkat Athmanathan, Terrence R. Meyer, Sukesh Roy, and Mikhail N. Slipchenko
Hybrid fs/ps coherent anti-Stokes Raman scattering (CARS) thermometry often utilizes ps probe pulses derived from pulse shaping or spectrally filtering the primary laser source or by synchronization with a low repetition rate external laser. This results in limited energy, spectral resolution, and/or repetition rate of the ps probe. In this work, a master-oscillator power-amplifier (MOPA) laser was
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Femtosecond Mamyshev oscillator at 920 nm Opt. Lett. (IF 3.1) Pub Date : 2024-04-15 Vincent Boulanger, Michel Olivier, Bertrand Morasse, François Trépanier, Martin Bernier, and Michel Piché
A femtosecond all-PM-fiber Mamyshev oscillator (MO) at 920 nm is presented. It is based on a neodymium-doped fiber with a W-type index profile that effectively suppresses the emission around 1064 nm. The linear cavity is bounded by two near-zero dispersion fiber Bragg gratings with Gaussian reflectivity profiles. The laser is self-starting and generates up to 10-nJ pulses at a repetition rate of 41
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Isochemical crystallization in condensed borate LaMgB5O10 glass-ceramics doped with optical probe Eu3+ Opt. Lett. (IF 3.1) Pub Date : 2024-04-11 Bartosz Bondzior
The isochemical glass-ceramics doped with Eu3+ were prepared by the heat treatment of lanthanum magnesium borate glass. The crystalline phase was chemically identical to a glass matrix and consisted of condensed borate LaMgB5O10. The isochemical crystallization process begins with the formation of rings by BO4 groups. The emergence of ordered crystalline phase gives rise to intense charge transfer
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Functional OCT reveals anisotropic changes of retinal flicker-evoked vasodilation Opt. Lett. (IF 3.1) Pub Date : 2024-04-11 Taeyoon Son, Guangying Ma, and Xincheng Yao
The purpose of this study is to verify the effect of anisotropic property of retinal biomechanics on vasodilation measurement. A custom-built optical coherence tomography (OCT) was used for time-lapse imaging of flicker stimulation-evoked vessel lumen changes in mouse retinas. A comparative analysis revealed significantly larger (18.21%) lumen dilation in the axial direction compared to the lateral
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Contrast-enhanced phase-resolved second harmonic generation microscopy Opt. Lett. (IF 3.1) Pub Date : 2024-04-11 Zhanshan Wang, Canyu Hong, Zeyuan Sun, Shuang Wu, Bokai Liang, Xidong Duan, Wei-Tao Liu, and Shiwei Wu
The characterization of inverted structures (crystallographic, ferroelectric, or magnetic domains) is crucial in the development and application of novel multi-state devices. However, determining these inverted structures needs a sensitive probe capable of revealing their phase correlation. Here a contrast-enhanced phase-resolved second harmonic generation (SHG) microscopy is presented, which utilizes
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Slow-light-enhanced Brillouin scattering with integrated Bragg grating Opt. Lett. (IF 3.1) Pub Date : 2024-04-12 Mingyu Xu, Peng Lei, Yunhui Bai, Zhangyuan Chen, and Xiaopeng Xie
Advancements in photonic integration technology have enabled the effective excitation of simulated Brillouin scattering (SBS) on a single chip, boosting Brillouin-based applications such as microwave photonic signal processing, narrow-linewidth lasers, and optical sensing. However, on-chip circuits still require large pump power and centimeter-scale waveguide length to achieve a considerable Brillouin