Applied optics最新文献

{"title":"High-precision thickness measurement via dual-path oblique laser triangulation and spatial-topological constraints.","authors":"Kaijin Wang, Bicheng Yuan, Youwei Xu, Nan Zhang, Weiquan Mo, Dawei Li, Kun Liu, Hao Sun","doi":"10.1364/AO.605323","DOIUrl":"https://doi.org/10.1364/AO.605323","url":null,"abstract":"<p><p>Laser triangulation is essential for industrial thickness measurement but faces challenges such as high noise sensitivity and non-uniform reflectivity. To address these issues, this paper presents a high-precision dual-path method based on a complementary optics-algorithm design that combines an oblique-incidence optical configuration with a spatial-topological constrained grayscale centroid method (STC-GCM). The dual-path configuration satisfies the Scheimpflug condition and is designed to enhance signal intensity, imaging quality, and stripe continuity. The STC-GCM integrates Otsu thresholding and morphological denoising with a constraint mechanism based on topological connectivity and geometric validity, thereby converting improved optical observability into robust valid-stripe selection. Comparisons show that the algorithm improves center-extraction accuracy by approximately 34% relative to the conventional GCM and achieves approximately 4× the computational efficiency of the Steger algorithm. Experiments over a 1.0-5.0 mm range yielded a maximum absolute error of 2.3 µm, a linearity of 0.058% FS, and a mean repeatability standard deviation of 0.90 µm. This technique provides a practical approach for high-precision industrial thickness monitoring under the evaluated conditions.</p>","PeriodicalId":101299,"journal":{"name":"Applied optics","volume":"65 29","pages":"10246-10255"},"PeriodicalIF":0.0,"publicationDate":"2026-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149229562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physics-aware restoration and calibrated soft demodulation for turbulence-degraded OAM mode recognition.","authors":"Pan Wang, Yuqing Luo, Wei Chen, Lixia Yang, Daisheng Zhang, Jun Zhu","doi":"10.1364/AO.605566","DOIUrl":"https://doi.org/10.1364/AO.605566","url":null,"abstract":"<p><p>Turbulence-degraded orbital angular momentum (OAM) mode recognition is critical for free-space optical (FSO) communication but is limited by atmospheric distortion. We propose a cascaded receiver integrating a vision transformer-based Uformer-OAM intensity-restoration network, an SE-ResNet-18 neural demodulator, and an entropy-modulated scaling (ETS) strategy for low-density parity-check (LDPC) soft decoding. In split-step beam propagation method (SS-BPM) simulations, Uformer-OAM achieves 31.34 dB peak signal-to-noise ratio (PSNR) and 96.9% recognition accuracy under strong turbulence (<i>C</i> _<i>n</i> ²=10^-13 m^-2/3, <i>z</i>=1000 m), outperforming UNet by 7.19 dB and 18.3 points, and the full cascade attains bit error rate (BER) <10^-6 at <i>z</i>=1300 m where baselines exhibit error floors.</p>","PeriodicalId":101299,"journal":{"name":"Applied optics","volume":"65 29","pages":"10044-10056"},"PeriodicalIF":0.0,"publicationDate":"2026-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149229604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Denoising of standoff ultraviolet Raman spectra under complex noise.","authors":"Yiming Lu, Ruiyu Lin, Kaike Cui, Hanyu Wang, Yuan Yao, Yongsen Xu","doi":"10.1364/AO.611369","DOIUrl":"https://doi.org/10.1364/AO.611369","url":null,"abstract":"<p><p>Accurate remote detection and identification of unknown substances under complex noise interference have long been a major research focus worldwide. Raman spectroscopy offers the unique advantage of providing molecular fingerprint information of target substances under noncontact conditions. However, complex noise sources, such as background light, detector noise, and long-distance transmission attenuation, can significantly reduce the distinguishability of weak spectral peaks. To address the difficulties in obtaining clean labels, the complexity of mixed noise, and the limited generalization capability of parametric filtering methods in remote measurements, an improved Noise2Void method incorporating a spectrally second-derivative-regularized loss, termed NN2V, is proposed. This method extends blind-spot learning from two-dimensional images to one-dimensional spectra. By masking the central sampling point, identity mapping is avoided, while the second-derivative-regularized loss constrains the local curvature of spectral lines, thereby suppressing high-frequency noise while preserving peak positions and intensities. In this study, a distance-simulation model based on the coupling of near-field measured signals and background noise was further constructed, and a 266 nm ultraviolet remote Raman transmitting-receiving system was established. Experimental validation was performed on solid calcium carbonate, sodium nitrate solution, trace hydrogen, and trace methane samples. Compared with Savitzky-Golay filtering, wavelet transform, and two deep learning-based methods, NN2V achieved a peak-intensity preservation ratio of 0.98 and improved the SNR of the trace hydrogen spectrum from 16.04 to 34.68 dB. The simulation and 10 m experimental results demonstrate that, under the current optical path, gating, and acquisition conditions, the proposed method can enhance the identifiability of weak Raman peaks in complex noise backgrounds. This study provides a feasible solution for denoising remote ultraviolet Raman spectra lacking clean labels under complex noise conditions.</p>","PeriodicalId":101299,"journal":{"name":"Applied optics","volume":"65 29","pages":"10235-10245"},"PeriodicalIF":0.0,"publicationDate":"2026-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149229688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cost-effective long-range measurement of structural displacement using a two-stage method integrating super-resolution reconstruction and sub-pixel registration.","authors":"Chi Zhang, Tiantian Li, Xuan Dai, Xiaosong Li","doi":"10.1364/AO.606610","DOIUrl":"https://doi.org/10.1364/AO.606610","url":null,"abstract":"<p><p>Displacement is an imperative metric for assessing structural performance. However, the accuracy of structural displacement measurement is constrained by the physical resolution of the camera, particularly in long-range monitoring scenarios. To address these constraints, a cost-effective long-range structural displacement measurement system based on a two-stage method integrating super-resolution reconstruction and sub-pixel registration (SRSR) is proposed in this study. Initially, the proposed method achieves texture detail enhancement of low-resolution images through super-resolution reconstruction, thus improving the accuracy of visual tracking. Subsequently, a continuous convolution operator based on natural texture on the structural surface is utilized to achieve accurate sub-pixel registration. Finally, the performance of the proposed methodology is verified with field tests on a scaled truss bridge and a cable-stayed bridge. The displacement measurement accuracy is significantly enhanced through the implementation of a two-stage technique based on SRSR (including steps I and II), in comparison to the utilization of the sub-pixel registration (step II only) in isolation. The cost-effective vision-based system developed in this study provides an alternative for long-range structural displacement measurement.</p>","PeriodicalId":101299,"journal":{"name":"Applied optics","volume":"65 29","pages":"9987-9995"},"PeriodicalIF":0.0,"publicationDate":"2026-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149229692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Defocus estimation for star sensors based on closed energy contours.","authors":"Hongzhe Chen, Wenbo Zhang, Weiguo Lu","doi":"10.1364/AO.612689","DOIUrl":"https://doi.org/10.1364/AO.612689","url":null,"abstract":"<p><p>This paper presents a novel, to our knowledge, defocus estimation method for star sensors, leveraging the equivalent radius <i>R</i>₈₀ of the 80%-energy closed contour in conjunction with pixel-phase compensation. In contrast to existing approaches, the proposed method operates on a single isolated-star-spot image and circumvents the need for complex parametric reconstruction of the point-spread function. The processing pipeline comprises background subtraction, noise suppression, centroid estimation, and pixel-phase compensation, followed by subpixel interpolation and threshold-based searching to extract the largest connected region that encloses approximately 80% of the total spot energy. The radius of an equal-area circle is then adopted as <i>R</i>₈₀, and a quadratic calibration model is established to relate <i>R</i>₈₀ to the axial defocus. Experiments conducted over a defocus range from -0.46875 to 0.46875 µm confirm that <i>R</i>₈₀ varies quadratically with defocus. Notably, pixel-phase compensation reduces the mean standard deviation of <i>R</i>₈₀ from 0.0426 to 0.0214 pixels, yielding a 49.8% improvement in repeatability. On independently acquired test images, the mean absolute bias of the seven position-wise mean estimates is 0.0092 µm. Owing to its single-image requirement and avoidance of iterative PSF fitting, the method is particularly well suited for practical focal-plane alignment and on-orbit image-quality assessment in star sensor systems.</p>","PeriodicalId":101299,"journal":{"name":"Applied optics","volume":"65 29","pages":"10024-10032"},"PeriodicalIF":0.0,"publicationDate":"2026-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149229665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-view consistent 3D light-field-driven display method for dynamic digital humans.","authors":"Haipeng Cui, Ningchi Li, Xinghua Yin, Binbin Yan, Qing Lang, Linxin Cai, Benzhi Yang, Xinzhu Sang, Xunbo Yu, Xin Gao","doi":"10.1364/AO.612511","DOIUrl":"https://doi.org/10.1364/AO.612511","url":null,"abstract":"<p><p>This paper proposes a multi-view consistent digital human reconstruction framework for three-dimensional (3D) light-field displays. Existing digital human reconstruction methods often emphasize single-view rendering quality, which may lead to geometric drift and cross-view inconsistency under dense-view display conditions. To address these limitations, an explicit facial mesh anchors Gaussian primitives through bounded residual offsets to improve geometric stability, while a spatial-angular attention network is embedded into 3D Gaussian splatting (3DGS) to jointly model fine-grained spatial details and view-dependent appearance. Furthermore, RGB, perceptual, and SSIM errors between rasterized images and ground-truth observations at calibrated camera viewpoints are back-propagated through the differentiable rasterizer to optimize Gaussian parameters; the physical light-field display is used for downstream validation. On temporally held-out test splits of three self-captured avatars, the proposed method achieves macro-average PSNR, SSIM, LPIPS, and FID values of 27.70 dB, 0.880, 0.097, and 18.71, respectively. The full model further achieves a warped cross-view error (WCVE) of 0.0213, compared with 0.0387 for the baseline. The generated digital humans exhibit improved geometric stability and view-dependent appearance consistency, enabling coherent 3D visualization on a physical light-field display.</p>","PeriodicalId":101299,"journal":{"name":"Applied optics","volume":"65 29","pages":"10344-10355"},"PeriodicalIF":0.0,"publicationDate":"2026-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149229575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermally reconfigurable full-space terahertz polarization-converting metasurface with physics-constrained forward prediction and attention-based inverse design.","authors":"Binggang Xiao, Zhonghua Wei, Zhitao Zhu, Hongmei Mi, Jiabin Yu","doi":"10.1364/AO.614551","DOIUrl":"https://doi.org/10.1364/AO.614551","url":null,"abstract":"<p><p>Reconfigurable terahertz polarization control is of growing importance for sixth-generation (6G) wireless communications, imaging, and sensing, yet simultaneously achieving broadband full-space operation, compact device architectures, and efficient design workflows remains a significant challenge. Here, we propose a thermally reconfigurable full-space terahertz polarization-converting metasurface composed of a 45°-rotated wrench-shaped gold resonator, a SiO₂ spacer, and an Au-VO₂ hybrid bottom grating. By thermally reconfiguring the bottom boundary via the VO₂ phase transition, the same compact platform switches between transmission-mode and reflection-mode polarization conversion without altering the unit-cell topology. The metasurface delivers a transmission polarization-conversion ratio above 90% from 0.30 to 6.66 THz and above 99% from 0.75 to 5.69 THz when VO₂ is in the insulating state, while maintaining a reflection polarization-conversion ratio above 90% from 2.44 to 4.56 THz when VO₂ becomes metallic. To accelerate electromagnetic modeling while ensuring physical interpretability and enabling on-demand design, we further develop a physics-constrained forward predictor, PhysiLSTM-Net, and an attention-enhanced inverse model, BiCAM-Net. By incorporating the polarization-conversion ratio into the loss function, PhysiLSTM-Net achieves an R² of 0.9802 with a mean-squared error (MSE) of 0.0051, whereas BiCAM-Net attains a mean R² of 0.951 across the target structural parameters and an RMSE of 0.269 in structural-parameter inversion. Together, the proposed device and learning framework establish a practical pathway toward broadband full-space terahertz polarization control and physics-guided intelligent metasurface design.</p>","PeriodicalId":101299,"journal":{"name":"Applied optics","volume":"65 29","pages":"10275-10284"},"PeriodicalIF":0.0,"publicationDate":"2026-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149229737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-fidelity 180° holographic reproduction: transition from analog Denisyuk to digital CHIMERA methods.","authors":"Yves Gentet, Philippe Gentet","doi":"10.1364/AO.609077","DOIUrl":"https://doi.org/10.1364/AO.609077","url":null,"abstract":"<p><p>We present a controlled experimental comparison between traditional analog Denisyuk reflection holography and the fourth-generation CHIMERA 180° digital holographic printing system for producing full-color, full-parallax 180° reflection holograms. Using the same object, scale, recording material, and reconstruction geometry, both workflows were evaluated for spatial resolution, parallax continuity, artifact formation, robustness, and practical applicability. The Denisyuk hologram exhibited slightly higher intrinsic spatial resolution, while the CHIMERA hologram produced visually continuous reconstructions with imperceptible hogel structure and improved background uniformity. The digital workflow eliminated plate-edge shadow artifacts and enabled the recording of fragile or vibration-sensitive objects without the stringent stabilization requirements of analog holography. Although the CHIMERA process required longer production times due to image acquisition and printing stages, it provided greater scalability, repeatable digital processing, and operational flexibility, including hologram replication at multiple scales and controlled volumetric image positioning. The results demonstrate that CHIMERA 180° holography can achieve perceptual realism approaching that of analog Denisyuk reflection holography while extending the range of objects and applications accessible to high-fidelity reflection holographic imaging.</p>","PeriodicalId":101299,"journal":{"name":"Applied optics","volume":"65 29","pages":"10088-10093"},"PeriodicalIF":0.0,"publicationDate":"2026-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149229415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution of interference and damage in a front-illuminated CMOS photodetector under 1064  nm high-repetition-rate nanosecond pulsed laser irradiation.","authors":"Shengqi Xu, Xiangjie Cao, Hailong Yu, Jing Shen, Canzhao Wang, Bing Zhang, Guangyan Dong, Guang Feng, Xun Gao","doi":"10.1364/AO.611425","DOIUrl":"https://doi.org/10.1364/AO.611425","url":null,"abstract":"<p><p>High-repetition-rate nanosecond pulsed lasers produce irradiation effects on CMOS photodetectors through the coupling between single-pulse transient photoelectric responses and multi-pulse thermal accumulation. The evolution from interference to damage under varying power and repetition rate conditions remains insufficiently understood. This study irradiated front-illuminated CMOS photodetectors with a 1064 nm high-repetition-rate nanosecond pulsed laser at average powers of 1 and 10 W with repetition rates from 1 to 3 MHz. A deviant pixel ratio method based on differential images and the 3<i>σ</i> criterion was established to quantify interference evolution and post-irradiation recovery. At 1 W, the detector sequentially underwent an initial transient response, black sun effect, interference expansion, and global saturation, recovering to near-baseline status after laser cessation. The recovery time extended from 402±67 ms at 1 MHz to 1809±67 ms at 3 MHz. At 10 W, the detector underwent readout sampling anomaly, saturation crosstalk, and cross-shaped functional damage with irreversible structural damage. The deviant pixel ratio at all repetition rates failed to fall below the single-pixel resolution limit after laser cessation, confirming irreversible functional damage that intensified with repetition rate. These results provide a basis for evaluating interference and damage effects of high-repetition-rate nanosecond pulsed lasers on CMOS photodetectors.</p>","PeriodicalId":101299,"journal":{"name":"Applied optics","volume":"65 29","pages":"10204-10211"},"PeriodicalIF":0.0,"publicationDate":"2026-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149229678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bio-inspired compound-eye receiver with a focal-length gradient and CPC arrays for wide-field underwater optical communication.","authors":"Dan Chen, Yongkang Zhou, Peiyan Zhao","doi":"10.1364/AO.610478","DOIUrl":"https://doi.org/10.1364/AO.610478","url":null,"abstract":"<p><p>Underwater wireless optical communication (UWOC) is faced with the problems of energy attenuation, light intensity flicker, and beam diffusion caused by turbulence, absorption, and scattering in the actual marine environment, which limits the performance of the receiver. In order to improve the receiving field-of-view angle and sensitivity, a UWOC receiver based on the bionic compound-eye structure is proposed in this paper. The receiver combines a curved sub-eye array with a focal-length gradient and a compound parabolic concentrator array (CPCA), which can efficiently converge the incident light from a large field of view to a small-area detector through the secondary focusing mechanism. Simulation results show that the design can significantly improve the energy transmission efficiency in the ±40^∘ field of view. Compared with the design without a focal-length gradient, the sub-eye design with a focal-length gradient improves the energy transmission efficiency by 8.9% at an incident angle of 40°. By building a water tank platform to simulate the ocean channel and adjusting the key parameters such as temperature, salinity, turbidity, and beam emission angle, the performance advantages of compound-eye lens in different channel conditions are verified experimentally.</p>","PeriodicalId":101299,"journal":{"name":"Applied optics","volume":"65 29","pages":"10314-10323"},"PeriodicalIF":0.0,"publicationDate":"2026-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149229759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}