Optics express最新文献

{"title":"Enhanced Tomlinson-Harashima precoding and adapted likelihood-based radius-directed equalization for transmitter-side bandwidth-limited faster-than-Nyquist systems over dynamic channels.","authors":"Jingpeng Liu, Kangyue Shen, Sheng Cui, Menghong Xu, Junjie Ou, Kaiyue Hu, Jianfeng Han, Tianhang Yao, Jing Dai, Ming Tang","doi":"10.1364/OE.600076","DOIUrl":"https://doi.org/10.1364/OE.600076","url":null,"abstract":"<p><p>The proliferation of bandwidth-intensive applications, such as AI cloud computing, has necessitated high-baud-rate transmission. However, this progression is often impeded by the transmitter-side bandwidth bottleneck, particularly in cost-sensitive short-reach scenarios. Although adaptive equalizers (AEQs) can mitigate such a bandwidth bottleneck, they do so at the cost of introducing equalization-enhanced high-frequency noise (EEHN), which severely degrades system performance. Tomlinson-Harashima precoding (THP) has emerged as a promising solution to counter this effect. However, its practical deployment is hindered by two critical limitations that this paper aims to resolve. First, conventional THP suffers from residual EEHN due to its inability to mitigate precursor inter-symbol interference (ISI). Second, its associated AEQ, which depends on training sequences for convergence, demonstrates unstable tracking performance over practical dynamic channels characterized by fast rotation of state of polarization (RSOP). To overcome these challenges, we propose an enhanced THP scheme at the transmitter to suppress the EEHN and a likelihood-based selection (LBS) radius-directed equalization (RDE) scheme adapted for THP-expanded constellations at the receiver (Rx) to ensure stable operation over dynamic channels. The effectiveness of the proposed scheme is validated through simulations and experiments. For a transmitter with a 3 dB bandwidth constrained to one-third of the baud rate, the proposed enhanced THP achieves approximately 1 dB sensitivity gain over conventional THP under static channel conditions. Under dynamic channels with a 500 krad/s RSOP, the AEQ relying solely on training sequences fails to converge, whereas the AEQ additionally incorporating payload symbols for RDE updates also suffers from notable degradation owing to frequent decision errors. In contrast, the proposed scheme operates reliably up to 1000 krad/s. At the 500 krad/s and 1000 krad/s RSOP speeds, it achieves a sensitivity improvement of over 1.5 dB and 3.8 dB, respectively. The proposed scheme offers a comprehensive solution for enhancing the performance of transmitter-side bandwidth-limited faster-than-Nyquist systems over practical dynamic channels.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"28100-28115"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148759228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polarization-independent electronic varifocal lenses via spatially dual-phase responses.","authors":"Yi-Hsin Lin, Hao-Hsin Huang, Wei-Cheng Cheng, Chang-Nien Mao","doi":"10.1364/OE.608661","DOIUrl":"https://doi.org/10.1364/OE.608661","url":null,"abstract":"<p><p>Polarization-independent electrically tunable liquid-crystal (LC) gradient-index spectacles are a major makeover of Benjamin Franklin's most famous invention, bifocal spectacles in 1784. However, response time (∼6 sec) is still a challenge. It motivates us to tackle the challenges of polarization-independent LC GRIN lenses: acceleration of operation and a dilemma between switching speed (response time) and optical phase. In this paper, we demonstrate polarization-independent electronic varifocal lenses via spatially dual-phase response. The mechanism of this lens is based on spatially dual-phase modulation composed of the Kerr phase in the central part and the orientational phase in the rest region. The response time is less than 10 msec as the lens power changes by 1.5 Diopters. In addition, the Kerr phase, proportional to the square of the electric field, is achromatic, but the orientational phase is chromatic. The operating principle is introduced and verified experimentally. The impacts of this study are not only in the application of spectacles but also in machine vision.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"28429-28439"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148761867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and experimental validation of a modified Dyson imaging spectrometer for solar-induced chlorophyll fluorescence detection.","authors":"Shanshan Zheng, Haisheng Feng, Jian Wen, Zhanjun Ling, Shuaiyin Lu, Su Wu, Lei Yu","doi":"10.1364/OE.604810","DOIUrl":"https://doi.org/10.1364/OE.604810","url":null,"abstract":"<p><p>Solar-induced chlorophyll fluorescence (SIF) imaging requires spectrometers with high spectral resolution, high throughput, and compact optical layouts. We present a modified Dyson imaging spectrometer for SIF detection, in which a lens-grating combination replaces the conventional concave grating to increase the slit-to-detector distance and improve linear spectral dispersion. The optimized system achieves a spectral resolution better than 0.3 nm, RMS spot radii below 7 <i>µm</i> across the full field of view, smile distortion below 1.4 <i>µm</i>, and keystone less than 2.75 <i>µm</i>. A prototype spectrometer was fabricated and calibrated. Measurements with an Hg-Ar lamp show a spectral full width at half maximum of 0.274-0.297 nm, and laboratory tests demonstrate a signal-to-noise ratio above 200 within the working band. Outdoor hyperspectral imaging experiments further verify the instrument performance, and SIF images of vegetation were retrieved at 762 nm using the 3FLD method. These results demonstrate that the proposed spectrometer provides an effective solution for high-resolution SIF imaging.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"27012-27026"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148762045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Frame-prior-constrained extrinsic refinement for stereo event camera calibration in a coaxial event-frame system.","authors":"Shiyue Du, Ji Liu, Boyang Zhang, Jinhui Wu, Menghai Zhang","doi":"10.1364/OE.606754","DOIUrl":"https://doi.org/10.1364/OE.606754","url":null,"abstract":"<p><p>Accurate stereo extrinsic calibration is essential for metric 3D reconstruction and motion tracking with event cameras. However, event-stereo calibration is often affected by sparse event observations, feature-localization uncertainty, and residual baseline or pose bias, which can be amplified during triangulation. This paper proposes a frame-prior-constrained extrinsic refinement method for a coaxial event-frame stereo vision system. The system uses a beam-splitter-based optical configuration in which each event camera and frame camera share an approximately common optical path. Based on this configuration, the calibrated frame-stereo extrinsics are introduced as geometric priors to regularize the event-stereo extrinsic refinement. The event-stereo rotation and translation are optimized by applying a local 6-DoF perturbation on the Lie group manifold. The physical baseline of the experimental stereo rig is approximately 316.5 mm, whereas the initial event-stereo baseline estimated from conventional event-camera calibration is 312.54 mm. After refinement, the event-stereo baseline is corrected to 316.32 mm, and improved 3D tracking accuracy is demonstrated in subsequent measurement experiments. These results demonstrate that the proposed frame-prior-constrained refinement improves the metric accuracy and geometric consistency of event-stereo 3D tracking.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"28745-28762"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148764330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Introduction to the feature issue 3D image acquisition and display: technology, perception and applications 2025.","authors":"Simon Thibault, Ana Doblas, Osamu Matoba, Artur Carnicer, Yuzuru Takashima","doi":"10.1364/OE.604884","DOIUrl":"https://doi.org/10.1364/OE.604884","url":null,"abstract":"<p><p>This joint feature issue of <i>Optics Express</i> and <i>Applied Optics</i> is organized in conjunction with the 2025 Optica conference on 3D image acquisition and display: technology, perception, and applications, which was held from 18 - 21 August as part of the 2025 Imaging and Applied Optics Congress in Seattle, United States. This feature issue presents 34 articles that cover the topics and scope of the 2025 3D image acquisition and display conference. This introduction provides a summary of the articles published in this feature issue.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"27531-27535"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148765156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated holographic vector matrix multipliers.","authors":"David J Brady, Andre Van Rynbach, Demetri Psaltis","doi":"10.1364/OE.607430","DOIUrl":"https://doi.org/10.1364/OE.607430","url":null,"abstract":"<p><p>We show that integrated optical volume holographic devices may implement arbitrary linear transformations with order unity efficiency. At the diffraction limit, the device area needed to implement an <i>N</i> × <i>N</i> transformation is proportional to <i>N</i>²<i>λ</i>², but in materials with a maximum index modulation of Δ<i>n</i>_max, the area scales as <i>N</i>³²<i>λ</i>²<i>Δ</i><i>n</i>_max. This scaling represents a factor of a <i>N</i> improvement over two-port device networks, such as Mach-Zehnder arrays. A holographic system may thus implement 1000 × 1000 transformations in 30 × less area and 10, 000 × 10, 000 transformations in 100 × less area. We explore the practical implications of these scaling laws in the design of electro-optically controlled holographic vector matrix multipliers.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"28187-28204"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148765220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heralded high-dimensional module-based quantum computation.","authors":"Xiao Zhang, Wen-Qiang Liu, Hai-Rui Wei","doi":"10.1364/OE.606666","DOIUrl":"https://doi.org/10.1364/OE.606666","url":null,"abstract":"<p><p>Parity measurements have been explored as building blocks for preparing and discriminating entangled states, as well as for implementing quantum computation. We first develop two alternative high-dimensional generalized parity modules, and then propose a procedure for constructing a high-dimensional generalized module-based controlled-NOT gate. The construction of module-based quantum computing introduced here is deterministic, heralded, and insensitive to the dimensionality of the computing basis, and a postselection technique is not required. The result shows that out of (<i>d</i> - 1)! generalized parity modules, only modules <i>P</i>=(<i>j</i>⊖<i>i</i>)mod<i>d</i> and <i>P</i>=(<i>j</i>⊕<i>i</i>)mod<i>d</i> can be used as building blocks for high-dimensional quantum computing. Furthermore, we proposed an optical nondestructive scheme for implementing a generalized parity module through quantum nondemolition measurements, and the success of the parity module is heralded by photon-number-resolving detectors and single-photon detectors.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"28401-28415"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148766451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"1.5 µm pulse-train self-optical parametric oscillator with tunable output based on an Nd:MgO:PPLN crystal.","authors":"Huaju Wang, Xiaodai Yao, Peilun Ni, Zijian Wang, Chao Wang, Hang Liu, Yongji Yu","doi":"10.1364/OE.607029","DOIUrl":"https://doi.org/10.1364/OE.607029","url":null,"abstract":"<p><p>This study demonstrates a 1.5 μm pulse-train self-optical parametric oscillator based on an Nd:MgO:PPLN crystal. A dynamical model is established to describe the self-optical parametric oscillation process, enabling analysis of the population inversion density together with the photon densities of the fundamental, signal, and idler waves. The results demonstrate that the subpulse number and subpulse interval can be precisely regulated by adjusting the pump repetition frequency, duty cycle, and Q-switching repetition frequency. Moreover, the pulse-train envelope can be shaped by tailoring the pump waveform to modulate the subpulse amplitude. Good consistency is observed between the theoretical results and experimental measurements. With a pump power of 40 W, the 1.5 μm pulse-train delivers a minimum subpulse width of 20.4 ns and a maximum average output power of 1.66 W, corresponding to a slope efficiency of 5.4%. This work provides an effective approach for flexible modulation of 1.5 μm pulse-train sources, offering a theoretical basis for compact 1.5 μm pulse-train lasers.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"28779-28795"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148766466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feasibility of entanglement-based QKD protocols with SPDC and quantum-dot sources.","authors":"Mariia Gumberidze, Vladyslav Usenko","doi":"10.1364/OE.590768","DOIUrl":"https://doi.org/10.1364/OE.590768","url":null,"abstract":"<p><p>We theoretically analyze the feasibility of entanglement-based quantum key distribution (QKD) protocols-both device-independent QKD (DI-QKD) and entanglement-based BB84 (EPR-BB84)-using widely employed spontaneous parametric down-conversion (SPDC) and what we believe to be a novel semiconductor quantum-dot (QD) sources. Within a unified photodetection-theory framework, we jointly evaluate the Bell parameter, quantum bit error rate (QBER), and asymptotic Devetak-Winter secret key rate for both source types, accounting for multiphoton emission in SPDC, fine-structure splitting (FSS) in the QD, and imperfect detection including finite efficiency and dark counts. Our results demonstrate that, despite the detrimental effect of FSS, QD sources achieve sufficient Bell violation and positive secret key rates under realistic experimental conditions. In contrast, within the standard CHSH-based DI-QKD framework and the detection and binning strategies, bare SPDC sources do not yield a positive secret key rate, despite the feasibility of loophole-free Bell tests with such sources. Our findings are crucial for the practical implementation of entanglement-based QKD protocols using realistic sources and detectors.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"27264-27279"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148765261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-precision absolute distance measurement based on double-pass intensity modulation with an S-G-filter-assisted wobbling algorithm.","authors":"Ju Wang, Ruize Zhang, Hao Luo, Xuemin Su, Chuang Ma, Jinlong Yu","doi":"10.1364/OE.609736","DOIUrl":"https://doi.org/10.1364/OE.609736","url":null,"abstract":"<p><p>A high-precision absolute distance measurement (ADM) system based on double-pass intensity modulation with an S-G-filter-assisted wobbling algorithm is proposed and experimentally demonstrated. In this scheme, the optical field is intensity-modulated by a Mach-Zehnder modulator (MZM) during the initial pass. After reflection from a target, it returns to the MZM along the same optical path, thereby realizing double-pass intensity modulation. By rapidly sweeping the modulation frequency, a frequency-sweep curve associated with the absolute distance is generated. The resulting frequency-sweep curve is smoothed using Savitzky-Golay (S-G) filtering, after which the wobbling algorithm is employed to locate two adjacent extrema. The absolute distance is then determined from the frequencies corresponding to the two adjacent extrema, and the ADM algorithm is implemented on a field-programmable gate array (FPGA) platform. Experimental results show that the proposed system achieves a relative measurement precision on the order of 10^-8 over a distance range from 1 to 100 m, which is realized by combining a single-mode fiber (SMF) delay path with an approximately 10 cm free-space path, with standard deviations of 0.17 μm at approximately 2 m and 8.91 μm at approximately 100 m.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"28440-28454"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148758933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}