Optics express最新文献

{"title":"Fabricating fiber cavity mirror substrates compatible with high coupling efficiency.","authors":"Michael Caouette-Mansour, Valeria Mosso Tsedilkina, Thomas J Clark, Jack C Sankey","doi":"10.1364/OE.608508","DOIUrl":"https://doi.org/10.1364/OE.608508","url":null,"abstract":"<p><p>Fiber optical cavities offer small mode volumes and correspondingly strong light-matter interactions in an open Fabry-Perot geometry. However, existing fabrication techniques do not reliably produce substrates with surface profiles amenable to high mode matching between the cavity mode and fiber core, thereby limiting the achievable collection efficiency. Here we present a technique to fabricate fiber mirror substrates while using <i>in situ</i> reflectometry to constrain the achievable mode matching prior to coating. By measuring the back-reflection from freshly cleaved fiber tips, we pre-select 138 fibers compatible with 96.5-99.5% mode matching, and after a single CO₂ laser ablation pulse, these fibers remained compatible with 95.3-99.2%. This simple technique provides rapid feedback during each stage of substrate fabrication, greatly enhancing the yield of viable fiber mirror substrates prior to (expensive) coating runs.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"27520-27530"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148762173","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":"Sequence-domain enhanced NOMA scheme for hollow-core fiber and W-band seamless integrated transmission.","authors":"Xiantao Yang, Bo Liu, Jianxin Ren, Yaya Mao, Qing Zhong, Zhiruo Guo, Shuaidong Chen, Jianye Zhao, Xiumin Song, Haojing Zhang, Na Li, Lei Dong, Feng Wang","doi":"10.1364/OE.605613","DOIUrl":"https://doi.org/10.1364/OE.605613","url":null,"abstract":"<p><p>This paper proposes a sequence-domain enhanced non-orthogonal multiple access (NOMA) scheme for hollow-core fiber (HCF) and W-Band seamless integrated transmission. In contrast to traditional power-domain NOMA that processes symbols on a symbol-by-symbol basis, the proposed scheme aggregates multiple consecutive quadrature phase shift keying (QPSK) symbols into high-dimensional sequences and maximizes the minimum Euclidean distance among the selected sequences through a subset selection process based on an annealing algorithm. This scheme combines sequence-level modulation with successive interference cancellation (SIC), effectively suppressing error propagation under low signal-to-noise ratio conditions while preserving the spectral efficiency of power-domain NOMA. Experiments in a photonics-assisted W-Band fiber-terahertz integrated system with 60 km HCF show that the optimal power division ratio (PDR) is 4 and the peak-to-peak voltage (Vpp) is 350 mV. At the same net rate, the proposed sequence-domain enhanced NOMA scheme achieves a 0.59 dB bit error rate (BER) gain over traditional NOMA at the 20% soft-decision forward error correction (SD-FEC) threshold. Selecting 16 sequence points has a BER performance improvement of 0.53 dB compared to selecting 32 sequence points. Moreover, under identical conditions, HCF outperforms standard single-mode fiber (SSMF) due to its lower nonlinearity and attenuation. The proposed scheme effectively enhances multi-user access reliability and adapts to channel conditions, providing a feasible technical path for future long-distance, high-capacity integrated transmission.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"28022-28034"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148762697","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":"Controllable auto-focusing characteristics of circular Airy-prime beam with grafted zero-order and fractional-order equivalent vortex phases.","authors":"Ruojun Wei, Junguang Ren, Liping Zhang, Benyi Wang, Haojie Li, Zhongsheng Man, Xiaolu Ge","doi":"10.1364/OE.607116","DOIUrl":"https://doi.org/10.1364/OE.607116","url":null,"abstract":"<p><p>Fractional optical vortex beam possesses a complex phase structure, which provides additional degrees of freedom for orbital angular momentum modulation. In this paper, a grafted zero-order and fractional-order circular Airy-prime beam with controllable auto-focusing characteristics is proposed. The grafted topological charges (TCs) can be flexibly selected in fractional forms, and the grafting angle <i>α</i> can be independently regulated. The focusing performance of the beam can be manipulated by <i>α</i> and the grafted TCs (<i>l</i>₁ and <i>l</i>₂). Furthermore, the focal intensity of the beam can be enhanced by introducing a thin convex lens at the initial plane. The focal positions and the number of focal spots can be precisely controlled by adjusting the lens focal length <i>f</i>. The work provides a feasible reference for the design of high-performance auto-focusing vortex beams and the precise manipulation of complex light fields.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"27081-27091"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148765177","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":"Quantitative THz time-domain single-pixel imaging using statistical scale-adaptive computational ghost imaging with random masks.","authors":"Yusuke Odagiri, Seigo Ohno, Katsuhiko Miyamoto","doi":"10.1364/OE.601097","DOIUrl":"https://doi.org/10.1364/OE.601097","url":null,"abstract":"<p><p>We present a terahertz time-domain spectroscopy (THz-TDS) approach integrated with single-pixel imaging (SPI) using a metallic random mask, enabling simultaneous acquisition of spatial and spectral information with high quantitative accuracy. While computational ghost imaging (CGI) provides excellent noise robustness, it typically yields relative correlation values, losing the quantitative scale proportional to the THz electric field. Conversely, ordinary least squares (OLS) reconstruction maintains quantitative scaling but is highly susceptible to noise due to the ill-conditioned nature of random masks. To overcome this trade-off, we introduce a statistical scale-adaptive computational ghost imaging (SSA-CGI) method that hybridizes the correlation-based stability of CGI with the quantitative scaling of OLS. This approach statistically transfers the quantitative voltage scale from OLS to the high-SNR CGI reconstruction, enabling accurate amplitude and phase mapping. The proposed technique was experimentally validated using a metallic aperture and patterned SU-8 structures, demonstrating spatially resolved spectroscopic imaging with high scaling fidelity and yielding group refractive indices consistent with reported values. Owing to its simple and robust configuration, the SSA-CGI method offers a practical, low-cost route toward quantitative THz spectroscopic imaging for applications in material characterization, nondestructive testing, and biomedical diagnostics.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"27906-27917"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148765230","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":"Reconfigurable nonlinear activation functions in an optomechanical whispering-gallery-mode microcavity.","authors":"Xin Sun, Wenxiu Li, He Yang, Linnan Jia, Hao Zhang, Zhisong Xiao","doi":"10.1364/OE.603534","DOIUrl":"https://doi.org/10.1364/OE.603534","url":null,"abstract":"<p><p>Optical neural networks (ONNs) have attracted significant attention for artificial intelligence because of their inherent parallelism. As a key component of ONNs, all-optical nonlinear activation functions (ONAFs) are critical to neural network performance. Here, we theoretically investigate reconfigurable nonlinear activation functions realized by optomechanically induced transparency (OMIT) in a whispering-gallery-mode microcavity. The proposed system can implement distinct nonlinear activation responses, including a smooth saturating response and a ReLU-like response. These responses can be continuously tuned through all-optical operation with microwatt-level thresholds. In compact neural network simulations, the proposed activation functions improve classification performance over the linear baseline on representative binary tasks with nonlinear decision boundaries. Further evaluation on MNIST and Fashion-MNIST using a compact convolutional neural network (CNN) yields accuracies of 98.93% and 98.88% on MNIST, and 91.16% and 89.70% on Fashion-MNIST. These results support the optomechanical effect as a promising mechanism for on-chip reconfigurable nonlinear activation in photonic neural computing.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"27348-27358"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148766296","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-quality reconstruction method for miniaturized lensless cameras based on imaging model optimization.","authors":"Kaiyu Chen, Ying Li, Zhengdai Li, Jiangtao Hu, Qizhen Zhao, Youming Guo","doi":"10.1364/OE.595581","DOIUrl":"https://doi.org/10.1364/OE.595581","url":null,"abstract":"<p><p>The multiplexing property of lensless imaging results in the encoded blur image being significantly larger than the effective scene region. The inherent contradiction between blur image truncation and reconstruction quality severely restricts the sensor miniaturization process. To address this issue, this paper proposes a high-quality reconstruction method for miniaturized lensless cameras based on imaging model optimization. This method applies a cropping operator to the scene image, making the reconstruction equations overdetermined, and effectively solves the underdetermined problem encountered when reconstructing from small-sized blur images. An improved Fast Iterative Shrinkage-Thresholding Algorithm (FISTA) is employed for basic scene reconstruction, combined with a U-Net network to further enhance the perceptual quality of the reconstructed image. Experimental results on the simulated dataset OCIFAR100_sim, the captured dataset OCIFAR100, and the public dataset PhlatCam show that, compared with traditional optimization algorithms and mainstream deep learning reconstruction algorithms, the proposed methods can achieve more stable and higher-quality scene reconstruction under small-sized blur image input conditions. This research provides theoretical support and technical pathways for the miniaturization of lensless camera sensors, with significant practical application value.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"26909-26925"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148759077","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":"Multi-state parallel reconfiguration of nanoprinting and holography in Ge₂Sb₂Se₄Te₁ phase-change metasurfaces.","authors":"Yafeng Huang, Ximin Tian, Junwei Xu, Shenglan Zhang, Zhi-Yuan Li","doi":"10.1364/OE.601103","DOIUrl":"https://doi.org/10.1364/OE.601103","url":null,"abstract":"<p><p>Metasurfaces enable exceptional optical wavefront manipulation at the subwavelength scale, underpinning diverse applications from structural-color nanoprinting to meta-holography. Although recent advances have integrated these dual functionalities within a single device, such platforms remain intrinsically static, constraining their practical utility. Here, we introduce a dynamically reconfigurable metasurface platform based on the phase-change material Ge₂Sb₂Se₄Te₁ (GSST), overcoming this fundamental limitation. By exploiting the orthogonal transmission properties of GSST meta-atoms and employing a phase-dependent spatial multiplexing strategy, we achieve precise control over the near-field electric field intensity distribution, enabling active switching of nanoprinting images. Simultaneously, the Pancharatnam-Berry phase is independently tailored within each pixel to manipulate the far-field wavefront for holographic projections, thereby realizing seamless integration of multi-state dynamic nanoprinting and multiplexed meta-holography. As a proof of concept, we numerically demonstrate two metasurface samples capable of triple-state, dual-mode dynamic switching, where both near-field patterns and far-field holograms are reconfigurable on demand. Furthermore, by incorporating the angular degeneracy associated with Malus' law, an additional near-field nanoprinting channel is established under orthogonal linear polarization paths, substantially enriching the functional dimensionality of the device. Building upon this platform, we further develop a high-security, multi-key, dual-level optical information encryption scheme that ensures robust physical-layer security against unauthorized access and information leakage. This work establishes a reliable and efficient pathway toward reconfigurable metasurfaces, unlocking opportunities for next-generation dynamic displays, advanced information encryption, optical anti-counterfeiting, and related applications.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"27918-27931"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148765038","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":"Physics-based forward modeling of edge diffraction scattering centers for complex coated scatterers.","authors":"Wei Gong, Siyuan He, Zhidan Bian, Zhihao Cai, Qi Huang, Hongcheng Yin","doi":"10.1364/OE.605500","DOIUrl":"https://doi.org/10.1364/OE.605500","url":null,"abstract":"<p><p>For low-observable targets, particularly those treated with material coatings, edge diffraction is an influential scattering mechanism. Although scattering center (SC) models can provide an effective sparse representation of local scattering mechanisms, the evolution from diffraction fields to SC models has not been systematically derived or quantitatively described for arbitrarily shaped edges and material coating conditions, which limits the accurate parameter characterization of edge diffraction SCs. Accordingly, this paper proposes an automated forward modeling method for coated edge diffraction SCs, grounded in the physical theory of diffraction (PTD). Spatial radiation expressions for straight edge and curved edge diffraction SCs are derived based on PTD and impedance boundary conditions. Then, geometric topology and visibility analyses are integrated to automatically identify, classify, and separate effective edge structures for given incidence directions. On this basis, physical correspondence from edge geometry, incidence conditions, and coating material properties to SC parameters is established, revealing the physical formation mechanisms of SCs and leading to an interpretable modeling method for edge diffraction from complex coated scatterers. Validated through comparisons with high-frequency methods and full-wave numerical simulations for typical edge diffraction structures and complex coated targets, the proposed method supports efficient and physically interpretable edge diffraction SC characterization, supporting physics-based analysis of target scattering responses.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"27708-27731"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148759473","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":"Full-chain model-driven cross-level multi-parameter collaborative optimization for electro-optical imaging systems.","authors":"Fafa Ren, Wenzhuo Qiang, Chao Zhang, Xiaorui Wang, Yue Li","doi":"10.1364/OE.603857","DOIUrl":"https://doi.org/10.1364/OE.603857","url":null,"abstract":"<p><p>Existing optimization approaches for infrared electro-optical imaging systems largely rely on analytical models based on linear approximations, while non-ideal imaging factors are rarely incorporated into a unified system-level design framework, limiting the reliability in performance prediction. To address the requirements for detection and recognition of infrared targets in complex scenes, a full-chain physical modeling framework for infrared electro-optical imaging is established, from radiative input through photoelectric conversion to grayscale image output, enabling a unified characterization of the nonlinear coupling among spectral response, spatial transfer, sampling, and noise. Based on this framework, simulated image contrast is adopted as the objective function. Key parameters, including F-number, pixel size, integration capacitance, veiling glare index, and the root mean square (RMS) radius of the aberration spot, are selected as design variables by analyzing the influence of system component parameters on the multidimensional propagation chain. Structural parameters and non-ideal imaging factors are thereby coupled within a unified performance evaluation space, enabling a cross-level multi-parameter collaborative optimization model that integrates performance optimization with physical constraints. A hybrid strategy combining global search via genetic algorithms and local search is employed to efficiently solve the resulting nonlinear optimization problem, and the feasible ranges of non-ideal imaging parameters are further inversely derived from system performance thresholds. Simulation results under land-background and sea-clutter scenes demonstrate stable convergence and significant contrast improvement, indicating strong cross-scene adaptability. The proposed framework provides a systematic approach for the digital collaborative design of high-performance infrared imaging systems in complex environments.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"28602-28619"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148759718","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":"Absorption tail analysis by spectroscopic ellipsometry: a reduced-parameter approach to electric field characterization in GaN.","authors":"Sha Han, Kai Li, Kebei Chen, Runnan Zhang, Juemin Yi, Yumin Zhang, Zhiwei Chen, Wentao Song, Ke Xu","doi":"10.1364/OE.600923","DOIUrl":"https://doi.org/10.1364/OE.600923","url":null,"abstract":"<p><p>We present a spectroscopic ellipsometry-based optical method for non-invasive, <i>in situ</i> electric field characterization via the absorption tail. The key advance is a reduction of the fitting problem from multiple free parameters to the reduced parameter by exploiting the intrinsic equivalence between the broadening factor <i>γ</i> and the space-charge region width <i>L</i>: for sufficiently large <i>L</i> (>90 nm), <i>γ</i> converges to zero. Unlike conventional Franz-Keldysh (FK) oscillation methods that require modulation spectroscopy and are restricted to wide, uniform fields, the absorption tail analyzed here persists under all field configurations-narrow or wide, uniform or non-uniform-making the approach universally applicable. Validated on three Si-doped GaN single crystals spanning carrier densities from 1.40 × 10¹⁷ to 3.20 × 10¹⁸ cm^-3, the method achieves a reduction in root mean square error up to 68.7%±41.2% compared to traditional multi-parameter approaches via Raman, KPFM, and ellipsometry. Requiring only standard broadband ellipsometry, the method is material-general and inherently compatible with external optical, electrical, and magnetic stimuli, establishing a practical platform for <i>in situ</i> optical field diagnostics in semiconductor and photonic devices.</p>","PeriodicalId":19691,"journal":{"name":"Optics express","volume":"34 15","pages":"28562-28574"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148760319","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}