Due to the in-situ antagonism and site competition during multi-ion coexistence in real water environments, traditional linear sensing models often fail. In this study, nitrogen-doped carbon dots (N-CDs) synthesized via a one-step hydrothermal method were used as a platform to investigate the microscopic response mechanism in Cu²⁺ and Fe³⁺ coexisting systems by constructing a 2D cross-fluorescence response matrix. Firstly, the fluorescence quenching evolution under different interference backgrounds was experimentally observed. The results showed that under a high concentration Cu²⁺ background, the fluorescence response induced by Fe³⁺ exhibited significant nonlinear shifts and quenching stagnation, confirming the intense exclusive competition between the two ions at the nano-interface. Subsequently, to analyze this nonlinear process, a "four-state physical kinetic model" was constructed based on the principle of detailed balance, and a global response analytical expression containing the thermodynamic synergy factor ($ \alpha $) was derived. Finally, a global surface fitting was performed on the experimental response matrix using the theoretical model. The results demonstrated a high degree of agreement between the theoretical fit and experimental data, yielding a synergy factor of $ \alpha $ ≈ 0.015. This extremely low value quantitatively confirms the extreme physical shielding and electrostatic repulsion effects constructed by high-valent ions. This study transforms cross-interference into quantifiable intrinsic thermodynamic parameters, which providing a solid theoretical foundation for nonlinear signal decoding and interface kinetics research in complex systems.

Single-frame image deblurring remains an inherently ill-posed problem. Furthermore, existing diffusion models suffer from high inference latency, while state space models lack sufficient cross-modal interaction capabilities. To overcome these limitations, we propose an end-to-end Event-fusion Multi-head Attention Network (EFMAN) that exploits high-frequency spatiotemporal priors from event cameras for high-quality image restoration. Specifically, a cross-modal adaptive attention mechanism is designed to precisely align asynchronous high-frequency event streams with synchronous RGB features in both spatial and temporal dimensions, thereby compensating for exposure deficiencies. To mitigate the impact of inherent sensor noise, a Feature Enhancement Attention (FEA) module bolsters feature robustness against noise via global context modeling. Additionally, a Lightweight Channel-Spatial Attention (LCSA) module is integrated to adaptively recalibrate feature responses while substantially alleviating computational redundancy. These components are optimized by a multidimensional joint loss function—encompassing pixel, feature, and gradient domains—to synergistically enforce multi-scale constraints, ensuring consistency between micro-textures and global topologies. Extensive experiments demonstrate that EFMAN significantly enhances deblurring performance while maintaining efficient inference. Compared to state-of-the-art methods, our approach achieves maximum PSNR and SSIM improvements of 1.19 dB and 0.005 on the GoPro dataset, and 0.38 dB and 0.003 on the REBlur dataset, respectively. By effectively addressing the challenges of multi-modal alignment and noise interference, EFMAN strikes an optimal balance between restoration quality and computational efficiency, making it highly suitable for clear image reconstruction in high-dynamic-range and rapid-motion scenarios.

As a critical component for spacecraft attitude measurement, inertial reference establishment, and rendezvous and docking missions, the stringent requirement for sub-arcsecond-level pointing accuracy in star cameras demands a compact optical mechanism and an opto-mechanical-thermal (OMT) integrated design. This paper presents a star camera based on a coaxial quad-reflector optical configuration. The primary and tertiary mirrors share a common substrate, achieving an effective aperture of 64 mm and a focal length of 195 mm. The four aspheric mirrors provide a ±2.5° field of view with an objective numerical aperture of 0.26. The system exhibits outstanding optical performance, with an MTF exceeding 0.7@40 lp/mm, approaching the diffraction limit. 80% encircled energy diameter ≤ 11 μm, absolute distortion not exceeding 0.1%. The system employs Zerodur^® glass ceramics and 4J32 Invar alloy, which coupled with a flangeless primary mirror and a compact 50 mm axial layout, ensure excellent thermal insensitivity. Coupled finite element analysis, using 36 Zernike polynomials, shows that within a temperature range of −40°C~60°C, the root mean square (RMS) surface error of the primary mirror remains below 6.19 nm. Rigid-body displacement is maintained within ±0.5 μm/10 K, MTF degradation remains below 20%, and the fluctuation of the 80% encircled energy diameter is less than 5 μm. Stray light suppression is achieved using a lightweight baffle ring with a multi-stage extinction cone. The extended baffle yields a Point source transmittance of 3×10⁻⁹ at 30° off-axis, improving stray light suppression by two orders of magnitude and enabling detection of faint 10th-magnitude stars. Thermal vacuum testing validated the system's performance, demonstrating a centroid positioning repeatability of 0.08 pixels and providing a valuable reference for the design of high-precision space optical payloads.

Terahertz (THz) wave modulation via metasurfaces exhibits considerable applications in THz communications, imaging, and detection. In this study, a molybdenum disulfide (MoS₂) metasurface is proposed to realize THz amplitude modulation at very low trigger voltages. The unit micro-nanostructure is characterized by a broken “H” shape linked by a MoS₂ layer. Simulation results indicate that the electrical control of the phase transition at the “H” junction can enable substantial amplitude modulation at 0.58 THz with a modulation rate of 98% and a low insertion loss of 20%. The modulation mechanism is elucidated by analyzing the electric field distributions at different structural positions and the diffraction patterns before and after the phase transition. To verify the design, electrical measurements in experiment are carried out on a MoS₂ layer with the same thickness of 2 μm and the resistivity of the measured MoS₂ layer varied by nearly six orders of magnitude with a minor change of the low trigger voltage from 0 to ±1 V, validating the feasibility of the interfacial metasurface control. This study is anticipated to offer a novel method for THz amplitude modulation, and promote the practical development of THz modulation devices.

All-aluminum opto-mechanical systems are promising for space remote sensing due to their athermal design capability, low cost, and rapid manufacturability. However, in practical engineering, structural constraints under mechanical and thermal loads often induce parasitic stresses within the opto-mechanical assemblies, which subsequently degrade optical stability. To address this, we propose an integrated opto-mechanical optimization scheme for a spectrometer's secondary mirror flexible support. Based on an opto-mechanical-thermal integrated analysis and dimensional sensitivity evaluation under gravity and a 5 °C temperature rise, a Kriging surrogate model was developed. This model integrates fundamental frequency and optical responses to optimize structural dimensions and select the most suitable optimization result. The optimization results demonstrate a 14.2% increase in the fundamental frequency to 204.6 Hz, along with reductions of over 21% in system wavefront aberration under both gravity and thermal loads. Experimental results confirms that the mirror surface root mean square is 0.021 λ (λ = 632.8 nm), and the system wavefront aberration across five fields of view remains consistently below 0.048 λ, fully meeting the technical requirements for stable imaging performance. The proposed method effectively enhances the thermo-mechanical-optical stability of all-aluminum spectrometers and offers a valuable design framework for precision opto-mechanical systems.

To address the challenge of simultaneously achieving a large scanning field of view and system miniaturization in underwater single-photon LiDAR, this paper proposes a technical solution based on mirror scanning and a sealed annular window. By establishing the geometric relationship between scanning angle, beam aperture, and mirror size, and integrating an annular water-isolated window structure, the system achieves miniaturization while maintaining a large scanning field of view. The initial optical system structure is built using ray tracing, and by applying the imaging and compensation principles of cylindrical optical elements, it improves the degradation of beam quality after passing through the annular window across different media. Integrated optimization with the telescope system further enhances beam quality. Experimental results demonstrate that the proposed system achieves a scanning field of view of 110°, a beam quality factor of less than 1.3 times the diffraction limit, a beam divergence angle of 0.084 mrad, and a transmission efficiency of 91.00%. The maximum detection range reaches 24m in water with an attenuation coefficient of 0.184m^-1. The proposed system provides both wide-field scanning capability and compact structural advantages, offering a potential solution for the engineering development of underwater wide-area detection platforms.

A multiple Fano resonance refractive index sensor based on metal-insulator-metal (MIM) waveguides coupled with dual D-shaped cavities is proposed. The transmission spectra and steady-state magnetic field distributions were simulated using the finite element method (FEM). The results show that the multiple distinct Fano resonances are observed, which are primarily attributed to mode hybridization between the vibration modes generated by the upper and lower D-shaped resonant cavities. Meanwhile, the influence of the geometric parameters of the D-shaped cavity on the Fano resonance was systematically investigated. Furthermore, the performance of the refractive index sensor based on multiple Fano resonances was evaluated. The results indicate that the sensor demonstrates excellent refractive index sensing performance, with a maximum sensitivity and a figure of merit reaching 1860 nm/RIU and 68.77 RIU⁻¹, respectively. This work provides a theoretical basis for the design of high-performance nanophotonic devices.

To improve star spot imaging quality and centroid extraction accuracy of event-based star sensors under high-dynamic conditions, and to address the issues of star trailing caused by conventional fixed-time integration, unstable image publication rate of adaptive-time integration, and the lack of continuous response levels in binary event-integrated images, this paper proposes a residual accumulating surface adaptive integration method for event-based star sensors. First, a progressive spatiotemporal denoising method is designed, which employs rapid spatial-domain preprocessing combined with spatiotemporal clustering refinement to suppress background noise events. Subsequently, an integration strategy combining a fixed publication rate with an adaptive event count is proposed, in which the number of integrated events is dynamically adjusted through elliptical morphology analysis of star spots, thereby suppressing star trailing while maintaining a stable a stable event-frame publication rate. A residual accumulating surface is then constructed using an exponential-decay recursive mechanism to continuously encode the event-triggering frequency, thereby forming a relative pseudo-grayscale response jointly determined by the event-triggering frequency and temporal recency. Finally, the residual accumulating surface is converted into a pseudo-grayscale star image via piecewise linear mapping, and sub-pixel centroid localization is accomplished through Gaussian fitting. Experiments on a real star event stream dataset demonstrate that, under a focal-plane image-motion velocity of 2272.7 pixels/s (equivalent to approximately 44°/s for a configuration with a 20° field of view and a 1024 × 1024 detector), the proposed method achieves a mean centroid extraction error of approximately 1.56 pixels and a mean star-pair angular distance error of approximately 3.35 arcsec, representing reductions of 58.3% and 19.1%, respectively, compared to the fixed 5 ms integration method. High centroid extraction accuracy is consistently maintained across the wide dynamic range of focal-plane image-motion velocities from 284 to 2273 pixels/s. The proposed method effectively suppresses star trailing and forms a star-spot pseudo-grayscale response distribution suitable for weighted centroid estimation, providing high-precision star-spot centroids for subsequent star identification and attitude determination.

To address the problem of interference fringe distortion and wind velocity retrieval errors caused by thermally induced surface deformation in a spaceborne long-wave infrared Doppler asymmetric spatial heterodyne interferometer operating in a low-temperature vacuum environment, a systematic study on aberration mechanisms and phase compensation methods was carried out. First, based on integrated opto-mechanical-thermal analysis, a surface deformation model of the optical system under the −113 °C operating condition was established. The surface errors were fitted and modeled using Zernike polynomials, revealing that thermally induced surface deformation primarily introduces low-order aberrations such as spherical aberration and astigmatism. Subsequently, the mechanism by which these aberrations generate additional optical path differences was analyzed. The results show that they lead to fringe bending, reduced contrast, and non-uniform spatial distribution, thereby degrading phase extraction accuracy and introducing wind velocity retrieval errors. Finally, a phase-domain compensation method based on Zernike polynomials was proposed to correct the interferometric phase and suppress the influence of thermally induced surface deformation on system performance. Simulation results demonstrate that the proposed method effectively restores the spatial characteristics of the interference fringes, reducing the wind velocity retrieval error by approximately 62.5%. This effectively mitigates the impact of thermal surface deformation and ensures wind measurement accuracy under extremely low-temperature conditions.

The exponential growth of large models and cloud computing is driving demand for unprecedented modulation speeds in short-reach data center links. While cavity-enhanced effects such as photon-photon resonance (PPR) and detuned loading (DL) offer a promising pathway, their practical implementation in directly modulated lasers (DMLs) often faces a critical trade-off: achieving a flat, high-bandwidth response typically requires complex fabrication techniques like butt-joint regrowth, whereas simpler identical active layer (IAL) designs suffer from uneven small-signal modulation response. In this work, we numerically investigate a dual-κ grating distributed feedback (DFB) laser based on an IAL structure that overcomes this trade-off. The design eliminates the need for butt-joint regrowth while effectively flattening the small-signal response. We compare its performance under single-ended and push-pull modulation schemes. The optimized laser exhibits a simulated small-signal modulation bandwidth of 185 GHz with multiple PPR peaks under single-ended modulation, and a simulated small-signal modulation bandwidth of 94 GHz with suppressed low-frequency roll-off under push-pull modulation. Notably, both schemes generate clear eye diagrams at 200 Gbit/s NRZ in simulation, demonstrating their potential for ultra-high-speed operation. Furthermore, tolerance analysis confirms robustness against typical fabrication variations. The proposed IAL-based dual-κ DFB laser therefore appears to be a promising cavity-design approach for future high-speed short-reach optical interconnects. Further work is still needed to address power efficiency and practical electrical bandwidth limitations.

As a critical component of integrated optoelectronic detection systems, multispectral ZnS windows enable multiband, common-path optical configurations. In this study, a broadband anti-reflection coating was designed and fabricated on multispectral ZnS substrates for multimodal detection applications covering the visible spectrum, the 905 nm laser band, and the long-wave infrared (LWIR) region. The residual stress, deposition process, coating design, and error sources of single-layer YbF₃ films were systematically investigated. By examining the effects of ion-source parameters on the stress of YbF₃ films, the optimal deposition conditions were determined to be a bias voltage of 150 V and a discharge current of 50 A. Initial experiments showed that the average transmittance in the visible band was only 73.35%. Inverse analysis indicated that this deviation was mainly caused by a systematic error in the tooling factor. After correcting the tooling-factor deviation and implementing an optimized monitoring strategy based on inverse spectral analysis, the layer-thickness error was effectively reduced, enabling precise control of highly thickness-sensitive layers. Normalized-coordinate analysis further revealed pronounced wavelength-dependent differences in spectral sensitivity between the visible and infrared regions. Therefore, a targeted single-band optimization strategy, combined with segmented monitoring of highly sensitive layers, was adopted to compensate for spectral shifts induced by cumulative thickness errors during multilayer deposition. The measured results show that, within an incidence-angle range of 0-15°, the average transmittance reached 93.57% at 450-1000 nm and 92.91% at 8000-12000 nm, satisfying the required performance specifications.

The performance instability and degradation of flexible and stretchable in-plane micro-supercapacitors (FS-MSCs) under large deformation have limited their applications. Selecting suitable flexible electrode materials and integrating them with stretchable substrates is crucial to solve the problem, while it remains a challenge to simplify the device preparation and optimize performance. Here, we report a programmable single-wavelength laser processing strategy that simultaneously reduces/patterns reduced graphene oxide (RGO) interdigital electrodes and textures an elastomeric substrate. By pre-stretching the substrate and fitting it to the flexible RGO electrodes, our device demonstrates excellent performance robustness. A bending angle of over 300° and a tensile strain of about 120% of its original length can be withstood. Furthermore, by optimizing the substrate surface morphology with ordered gridding, the electrochemical properties and stability of the device have been significantly improved, which achieves a maximum capacitance of 1.34 mF/cm² with a fluctuation of only 1.5% under different tensile conditions. Even as the current density increases from 0.01 to 0.05 mA/cm² gradually, the specific capacitance fluctuation of the devices remains <7.4% under varying tensile strengths. Our work offers an effective solution for enhancing performance stability of in-plane FS-MSCs in harsh deformation environments, holding great potential for their future applications in wearable and portable energy storage.

In the study of the dynamic characteristics of plasma shock waves generated by the 351 nm deep-ultraviolet high-intensity laser acting on stainless steel metal, there is an urgent need for an ultra-fast dynamic pressure sensor with a response time of less than 50 nS. To this end, this paper describes an ultra-miniature ultra-fast air shock wave pressure sensor based on a Fizeau cavity fabricated on the end face of an optical fiber. A static calibration test and a dynamic calibration test are conducted using a piston-type pressure calibration machine and an air shock tube. When the response time of the high-speed photodetector is 8 nS and the resonant frequency point is 20 MHz, the calibration results indicate that the repeatability, hysteresis, nonlinearity, and the overall measurement accuracy of the sensor within the full pressure range of 2.4 MPa are 1.117%, 1.046%, 1.09%, and 3.253%, respectively. and dynamic response time is less than 50 nS. In actual experiments, the sensing system successfully captures the plasma shock pressure wave produced on stainless steel upon irradiation by a 351 nm deep-ultraviolet high-intensity laser. To the author’s knowledge, It is the first time to utilize a shock wave pressure sensor to capture the ultrafast plasma shock pressure wave generated by high-power laser-induced stainless steel metal. Finally, the potential application directions of this ultrafast dynamic pressure sensor is pointed out.

In space-based gravitational wave detection, the Point-Ahead Angle Mechanism (PAAM) is crucial for high-precision pointing of intersatellite laser links, but its rotation introduces tilt-to-length (TTL) noise that severely limits interferometric accuracy. To suppress local TTL noise caused by PAAM angular jitter, this paper proposes an imaging system that optically images the detector onto the equivalent rotation center of the PAAM, actively mitigating geometric TTL noise. A highly symmetric equal-arm heterodyne interferometer test platform was constructed, and IFOCAD simulations were performed to evaluate suppression performance under non-ideal conditions (angular jitter, rotation center offset, installation errors, thermal deformation). Results show that under ideal alignment, the imaging system suppresses 98.9% of lever-effect optical path changes and 98.2% of piston-effect changes. With installation errors, TTL noise is suppressed within $ 1\;\text{pm/}\sqrt{\text{Hz}} $, and remains below $ 10\;\text{pm/}\sqrt{\text{Hz}} $ when thermal noise is introduced. Simulations confirm that lever noise has a second-order correlation with angular jitter, while piston noise has a first-order correlation, consistent with theoretical analysis. This study provides theoretical and simulation support for designing high-stability beam pointing control systems and assessing noise in future missions.

In space gravitational wave detection missions, interferometer arm lengths dynamically evolve under the influence of orbital dynamics, making it difficult for traditional equal-arm homodyne models to describe the propagation characteristics of quantum noise in heterodyne links. To address the non-zero coupling between laser-port noise and dark-port fluctuations caused by dynamic unequal-arm heterodyne interferometers in space gravitational wave detection, this paper derives a full-band quantum noise evolution model and obtains an adaptive control criterion for the optimal squeezing angle. Starting from time-dependent field operators, the frequency-domain noise mixing matrix is derived by using the Fourier transform to convert time-domain causal delays into frequency-domain phase rotations. Combined with the optomechanical coupling coefficient to describe low-frequency radiation pressure noise, a universal optimal squeezing angle criterion for the full frequency band of space gravitational wave detection is established. Numerical simulations demonstrate that when the static phase difference reaches its maximum, the traditional fixed squeezing angle scheme fails to suppress the mixed noise, with its normalized variance remaining at 1.0. In contrast, the proposed adaptive squeezing angle scheme exhibits a significant noise reduction effect; at squeezing parameters r = 0.5 (4.3 dB) and r = 1.0 (8.7 dB), it successfully reduces the normalized output phase noise variance to 0.9046 and 0.7483, respectively. Utilizing this criterion to dynamically adjust the squeezing direction can enhance the level of quantum noise suppression across the full frequency band of space gravitational wave detection, providing a theoretical reference for quantum noise mitigation in space gravitational wave detectors under dynamic unequal-arm environments.

Space-based gravitational wave detection missions require the on-board laser to exhibit extremely low frequency noise. To meet this requirement, the frequency noise of a free-running laser, especially its low-frequency components, must be suppressed by approximately five orders of magnitude through a laser frequency pre-stabilization system, achieving a level below 30 Hz/√Hz (1 mHz–1 Hz). This stringent specification imposes a demanding requirement on the temperature stability of the reference cavity module—the core component of the laser frequency pre-stabilization system—which must achieve precision thermal control near its coefficient of thermal expansion (CTE) null point. In this paper, we focus on the precision thermal control requirements of the engineering prototype of a on-board frequency pre-stabilization system, and specifically on its reference cavity module. A cascaded precision thermal control scheme combining a two-stage thermal control architecture is designed and verified on the ground. This scheme employs an constant temperature cage as the first-stage active temperature-stabilized shield, coupled with a second-stage passive thermal isolation layer to implement two-stage control, suppressing the temperature fluctuation of the reference cavity vacuum chamber to below 1 mK, ensure the length stability of the optical reference cavity. The overall thermal control design, system simulation, detailed thermal control implementation, and the experimental results of equivalent ground verification are elaborated. The experimental results demonstrate that under a simulated on-board environmental disturbance of ±1 K, the designed precision thermal control scheme can maintain the reference cavity module temperature stably at the target set-point with a temperature stability better than 0.3 mK for a duration exceeding 2000 s. This performance satisfies the precision thermal control requirements of on-board frequency pre-stabilization system for space-based gravitational wave detection, providing key technical support for subsequent engineering development.

Traditional three-dimensional digital speckle interferometry generally relies on synchronized multi-beam, multi-wavelength, or multi-camera configurations to obtain three-dimensional displacement vectors, which often leads to complex optical setups, dimensional coupling, and difficulties in synchronizing dynamic processes. To overcome these limitations, this paper proposes a three-dimensional dynamic displacement-field measurement method that integrates digital holographic speckle interferometry with event vision. First, holographic interference patterns are recorded by an industrial camera combined with a spatial phase-shifting technique, enabling high-precision phase reconstruction of out-of-plane micro-deformation on the object surface. Then, an event camera is introduced to asynchronously capture speckle-intensity variations on the surface for in-plane displacement measurement. The event stream is temporally accumulated, and a block-matching algorithm is used for displacement estimation. Finally, the highly sensitive out-of-plane phase information is fused with the in-plane displacement data to reconstruct the complete three-dimensional displacement field. Experimental results show that the proposed digital holographic speckle interferometry–event vision fusion system can stably measure the three-dimensional displacement field of circular thin plates. The minimum RMSE values reach 0.47 μm for out-of-plane displacement, 0.18 μm for in-plane displacement, and 0.13 μm for the fused three-dimensional displacement field. The proposed method generally satisfies the requirements of high precision, good stability, and strong anti-interference capability in three-dimensional micro-deformation measurement.

Narrow-FOV, long-focal-length star sensors suffer from roll-axis degradation and ill-conditioned observation geometry. This paper builds a weighted global Fisher information matrix model. A-, D-, and E-optimality criteria are used to derive optimal multi-FOV pointing relations. A multi-sensor Wahba fusion (MSWF) method is then developed. The analysis shows that orthogonal two-FOV and three-FOV configurations, and a tetrahedral four-FOV configuration, improve three-axis information distribution under equal weights. Simulations with a dual-FOV off-axis TMA star sensor show that the ill-conditioned-axis error of a single FOV is about 38 times that of the other axes. The orthogonal dual-FOV configuration with MSWF reduces the total attitude error by 95.4% relative to a single FOV and by 29.2% relative to simple averaging. It also maintains balanced three-axis performance under sparse-star, random-loss, and motion-blur conditions. The results show that optimized multi-FOV geometry and weighted star-vector fusion can mitigate the geometric limitation of a single FOV.

Ultra-short pulse lasers operating in the 2μm band boast unique merits such as eye safety and compatibility with atmospheric transmission windows, endowing them with immense application value in national defense, medical treatment, communication, scientific research and other fields. As a core method to generate such ultra-short pulses, passive mode-locking technology has become a research hotspot in the field of solid-state lasers. This paper systematically reviews the latest research advances in 2 μm-band passively mode-locked solid-state lasers. Firstly, it elaborates on the fundamental principle of passive mode locking, analyzes the physical mechanisms of diverse mode-locking schemes including Kerr lens mode locking(KLM), and introduces the energy level dynamic characteristics of Tm³⁺, Ho³⁺ and their co-doped systems as gain media. Afterwards, three mainstream technical routes, namely Kerr lens mode locking, semiconductor saturable absorber mirror mode locking and low-dimensional nanomaterial mode locking, are discussed in detail as the key focus. This paper compares the performance and implementation approaches of different mode-locking schemes, summarizes the research achievements of various passively mode-locked lasers, and meanwhile discusses and prospects the future development of 2 μm-band passively mode-locked solid-state lasers.

Conventional detection methods based on OAM intensity spectra can identify the presence of gear defects but fail to determine the specific azimuthal positions of missing teeth due to the loss of phase information. To address this limitation, this study simulates the scanning of intact and defective gears using vortex beams with varying topological charges. By incorporating a four-step phase-shifting algorithm based on ideal plane waves, we construct an OAM complex spectrum that retains helical phase information. This spectrum extracts the azimuthal characteristics of the gear, enabling the accurate determination of both the position and the index of missing teeth. Furthermore, this study investigates the impact of base circle parameters and tooth height on defect measurements in non-trivial sector targets. The results demonstrate that the relative amplitude difference between defective and adjacent intact gear signals is highly dependent on these geometric parameters. Specifically, when the fundamental mode waist radius is fixed at 6 mm, increasing the tooth height from 2 mm to 4 mm enhances the signal amplitude difference, whereas increasing the base circle radius from 10 mm to 14 mm diminishes it. Ultimately, this research provides preliminary insights and a viable pathway toward high-precision, non-contact gear defect localization based on the OAM scanning.

Objective: This study addresses fringe-based three-dimensional measurement of local structures on complex reflective printed circuit boards. Uniform image interpolation may distort sinusoidal fringes. Curved fringes may also cause a mismatch between the interpolation direction and local iso-phase lines. Low-modulation regions may further amplify phase errors.Methods: A measurement-oriented phase-preserving fringe super-resolution resampling method is proposed. The super-resolution operation is performed in the gray-image domain. Phase-domain quantities are used as physical constraints. First, a normalized carrier intensity index is used to decouple fringe ridges, valleys, and transition regions. Ridge-valley distance and local modulation are then combined to construct a joint weight. Next, a two-dimensional fringe-alignment displacement field is estimated from multi-frequency phase-shifting data. The field is refined by local correlation and two-dimensional total-variation regularization. The original fringe images are then mapped into an aligned domain for directional interpolation. Finally, a flat/steep-region adaptive fusion strategy is constructed using the displacement-field gradient and local phase variation rate.Results: In the 3 mm, 6 mm, and 9 mm gauge-block experiments, the proposed method reduced the mean absolute error from 0.0290 mm to 0.0208 mm. It also reduced the root mean square error from 0.0428 mm to 0.0295 mm. In the high-reflective PCB pin region and the crystal oscillator package region, the proposed method improved phase continuity and three-dimensional reconstruction stability. In the pin region, compared with image-domain bicubic interpolation, the proposed method reduced the mean absolute error from 0.1753 mm to 0.0254 mm, corresponding to a reduction of about 85.5%. The error standard deviation was reduced to 0.0126 mm.Conclusion:The proposed method improves phase consistency after fringe resampling, increases point-cloud sampling density, and reduces local reconstruction errors in the selected PCB regions. This super-resolution process should be interpreted as sampling-grid densification and interpolation-induced phase-error reduction, rather than as exceeding the true lateral resolution limited by the optical system. The current conclusions are limited to the tested PCB local ROIs and imaging conditions.

Time-interleaved analog-to-digital converters (TIADCs) overcome the sampling rate bottleneck of monolithic ADCs and enable ultra-high-speed broadband acquisition of optical signals in applications such as laser 3D imaging lidar and high-speed optical communication systems. However, their practical performance is fundamentally limited by inter-channel mismatches in offset, gain, and sampling timing, which introduce pronounced spurious components and nonlinear distortion. Such errors directly degrade the sampling accuracy of laser echo signals and impair system ranging and demodulation performance. To address this issue, this paper proposes an all-digital TIADC calibration algorithm based on a multi-channel all-phase fast Fourier transform (FFT) frequency discriminator. A two-stage low-pass filtering and interpolation reconstruction architecture is devised, paired with the multi-channel all-phase FFT frequency discriminator. By exploiting the phase invariance property of all-phase FFT and the phase correlation of multi-channel sampling, the proposed method achieves high-precision frequency estimation and interval discrimination of input signals, which eliminates the inherent high-frequency performance deterioration of traditional algorithms. Integrated with a least mean square (LMS) adaptive filtering framework, the algorithm realizes synchronous joint calibration of offset, gain, and sampling timing mismatch errors. A 4-channel TIADC experimental platform with a total sampling rate of 2 GHz is constructed based on MATLAB and FPGA for performance verification. Experimental results demonstrate that the proposed frequency discriminator maintains a frequency interval discrimination accuracy of 96.7% even at an extremely low signal-to-noise ratio (SNR) of −5 dB. After calibration, the spurious-free dynamic range (SFDR) of the system is improved from 19.8 dB to 81.2 dB, and the signal-to-noise and distortion ratio (SNDR) reaches 73.8 dB. The proposed algorithm operates without dedicated calibration signals and exhibits outstanding calibration performance under low-SNR conditions, providing core technical support for high-speed, high-precision sampling systems in optical fields including lidar and high-speed optical communication.

To address the limitations of conventional conjugate vortex beam interference-based micro-displacement measurement methods, including limited rotation-angle variations of interference patterns and insufficient capability for sub-nanometer displacement detection, a micro-displacement measurement method based on opposed dual-surface differential conjugate vortex beam interference is proposed. The proposed method exploits the linear relationship between the rotation angle of the conjugate vortex interference pattern and the phase difference between two interferometric paths, converting micro-displacement into the angular rotation of petal-shaped interference patterns. To overcome the constraints imposed by camera pixel resolution and pattern distortion on tiny rotation-angle extraction, an opposed dual-surface differential optical path is developed, where two conjugate vortex beams interact with opposite surfaces of the same target. Compared with the conventional single-surface reflection configuration, the proposed structure doubles the relative optical path difference, thereby theoretically doubling the interference-pattern rotation angle under identical displacement conditions. Furthermore, an H-Nets model based on circular harmonic convolution is introduced to extract rotation-equivariant features from the rotating interference patterns. Continuous angular variations are encoded as phase shifts in the complex-valued feature space, enabling stable characterization of tiny rotation angles and accurate displacement inversion. Experimental results demonstrate that, within a displacement range of 0–500 nm, the maximum absolute error is below 0.61 nm, with a mean absolute error of 0.37 nm. The proposed method achieves enhanced micro-displacement measurement accuracy and stability through the synergistic integration of differential optical-path amplification and rotation-equivariant feature decoding.

To address the issue of compensator coupling in the tolerance analysis of high-numerical-aperture microscope objectives, this paper proposes a compensator selection method based on the cosine similarity of the V-matrix, aiming to reduce negative correlations between compensators and avoid problems such as coma and astigmatism that cannot be simultaneously corrected. Taking an infinity-conjugate microscope objective with a numerical aperture of 0.9 as the subject of study, a sensitivity matrix between structural parameters and aberration parameters was constructed using the first-order finite difference method. By employing V-matrix cosine similarity and a weighted greedy strategy, six effective compensators were identified. Experimental results show that the cumulative probability of the system’s wavefront aberration RMS being less than 0.07 λ increased from 47% to 97.7%, while manufacturing and alignment tolerances were reduced from Q1 to Q2 grade, significantly lowering the manufacturing tolerances of the optical system and effectively improving system yield. Alignment simulation experiments further validated the feasibility and effectiveness of this method in high-numerical-aperture microscope objectives. These results demonstrate that this method can select appropriate compensators and effectively reduce the negative correlation among them.

The near-infrared optical absorption and photoresponse of silicon-based optoelectronic devices are intrinsically limited by the bandgap of silicon. Picosecond laser-induced Se doping combined with surface micro/nanostructuring provides an effective approach to enhancing the near-infrared performance of silicon. Among the relevant processing parameters, laser energy density plays a critical role in governing microstructure evolution and dopant redistribution, thereby strongly influencing device performance. In this study, single-crystal silicon substrates coated with a Se film were irradiated using a picosecond laser at energy densities of 0.85, 1.40, and 1.71 kJ/m². Se-doped N⁺−N silicon photodiodes were subsequently fabricated to systematically investigate the effects of laser energy density on surface micro/nanostructure, optical absorptance, and photoelectric performance. The results show that the overall crystalline structure of the samples remains well preserved under all processing conditions, whereas their surface microstructures differ markedly. These structural variations further affect the optical absorption and device photoresponse. At an energy density of 1.40 kJ/m², the sample exhibits the most uniform surface micro/nanostructure. Optical and electrical measurements show that its near-infrared absorptance exceeds 60%, while the corresponding photodiode achieves a responsivity of 2.28 A/W at a reverse bias of −6 V under 1064 nm illumination. These findings demonstrate that picosecond laser energy density plays a significant role in regulating the surface microstructure, near-infrared absorption, and photoresponse of Se-doped silicon. This study provides experimental guidance for optimizing the fabrication and performance of Se-doped black-silicon near-infrared photodetectors.

The integration of metasurfaces with optical sensors can effectively reduce the sensor volume and enhance its capability for electromagnetic field manipulation. This paper proposes and fabricates an all-dielectric multifunctional metasurface optical sensor based on a disk-with-double-gap silicon array on a quartz substrate. By introducing two asymmetrically arranged gaps oriented at 45° to break the structural symmetry, the proposed structure successfully converts the non-radiative ideal bound state in the continuum (BIC) into a high-Q quasi-BIC state with strongly localized optical fields, and excites an ultra-narrow linewidth Fano resonance sensing peak at 1617 nm. Simulation results indicate that the resonance peak is predominantly contributed by the magnetic dipole (MD) mode, with a theoretically maximum quality factor (Q) of up to 1.6×1051.6×10⁵ and a figure of merit (FOM) reaching 36350. The sensor exhibits a refractive index sensitivity of 363.5 nm/RIU and a temperature sensitivity of 51.96 pm/°C. Furthermore, the modulation depth of the metasurface resonance peak can be controlled by varying the polarization state of the incident light. Experimental sensing analysis demonstrates a sensitivity of 268.7 nm/RIU for liquids with different refractive indices. This structure holds promise for applications in environmental monitoring, biomedical detection, polarization-controlled optical switching, and provides a reference for multi-parameter metasurface sensors, extending the multifunctionality of metasurfaces in practical sensing applications.

To address the issues of insufficient adaptability in cross-view feature fusion and inadequate utilization of complementary information in existing dual-view X-ray security inspection image prohibited item detection methods, this paper proposes an improved dual-view fusion detection method combined with YOLOv11 (Dual View Fusion combined with YOLOv11, DVF-YOLOv11). The proposed method employs a parameter-shared dual-branch YOLOv11 backbone network to extract multi-scale features from the overlook-view and side-view images, respectively. A Cross-View Attention Fusion (CVAF) module is designed to adaptively enhance dual-view features through a cascaded mechanism of channel attention and spatial attention. An adaptive weight prediction network is introduced to dynamically adjust the fusion weights of each view, and is combined with channel compression convolution to form a dual-path fusion strategy. A joint loss function composed of feature preservation loss, complementarity loss, and weight balance loss is further designed to guide the fusion learning process. On the DvXray dataset, the proposed method achieves an mAP50 of 94.02% and an mAP50-95 of 79.41%, improving by 2.99% and 5.29%, respectively, over the single overlook-view baseline. Experimental results demonstrate that the proposed method improves the accuracy and robustness of prohibited item detection in dual-view X-ray security inspection images.

During on-orbit operation, space cameras are exposed to complex thermal environments. Non-uniform variations in the structural temperature field can induce thermoelastic deformation, leading to line-of-sight (LOS) pointing deviations and significantly degrading imaging accuracy and stability. To address the insufficient robustness of the traditional Least Squares (LS) method in analyzing LOS pointing stability of space cameras under complex thermal conditions, this paper proposes a thermal line-of-sight pointing analysis method based on the Iteratively Reweighted Least Squares (IRLS) algorithm. First, a thermo-structural coupled model of the space camera is established to analyze the mapping relationship between temperature field variations and LOS pointing deviation. Then, the IRLS algorithm is introduced to perform robust estimation of model parameters. By constructing a weighted residual function, the influence of abnormal measurement data on parameter identification is effectively suppressed, thereby improving the prediction accuracy of thermal deformation. Meanwhile, an energy-iterative window adaptive centroiding algorithm is adopted to capture the variation of spot centroid positions with temperature changes. To investigate thermally induced pointing drift of the on-orbit camera, thermal experiments are conducted. Simulation results are further validated using ground-based thermal test data, and the performance of the proposed IRLS method is compared with that of the traditional LS method in terms of pointing error prediction accuracy and convergence characteristics. The results demonstrate that the proposed IRLS-based thermal analysis method significantly improves the prediction accuracy of LOS pointing deviation in the presence of measurement noise and outliers, while enhancing the stability and robustness of the model. This approach provides an effective technical solution for on-orbit thermal deformation compensation and accuracy maintenance of high-resolution space cameras.

In real-time brain neural observation of freely moving animals, the miniature head-mounted fluorescence microscope is currently one of the most advanced brain science observation instruments. However, most existing miniature fluorescence microscopes, in order to meet strict size and weight constraints, have a limited field of view, making it impossible to simultaneously observe neural activity in multiple brain regions. On the other hand, a few products with a larger field of view are too heavy to be worn on small animals. This study employs lightweight, planar, and high-quality gradient refractive index lenses to reduce the microscope's weight while ensuring a large field of view. Using gradient refractive index lenses for the design of a large-field-of-view miniature fluorescence microscope, this research derives the off-axis aberration formula for oblique light incidence on gradient refractive index lenses, analyzes the refractive index distribution model and aberration correction of these lenses, and designs a miniature fluorescence microscope with a 4 mm×4 mm field of view, a numerical aperture (NA) of 0.1, and a prototype weight of only 2.89 g. The central visual field resolution is 13.9 μm, preliminarily achieving the resolution for neural cells in freely moving mice.

Aiming at the problem that existing spectral compressed sensing algorithms adapted to the visible band are difficult to achieve high-precision reconstruction for sharp gas absorption features in the mid-wave infrared (MWIR) spectra, this paper proposes a physics-driven MWIR spectral compressed encoding and reconstruction network to realize high-precision reconstruction of MWIR spectra with sharp gas absorption features. The dual-branch MWIR spectral reconstruction network serves as the core module of the proposed framework. Specifically, the network consists of two parallel branches, namely the smooth background reconstruction branch and the characteristic absorption reconstruction branch, which respectively realize the accurate reconstruction of smooth background logarithmic spectrum and sharp gas characteristic absorbance. Subsequently, high-accuracy reconstruction of MWIR gas absorption spectra is achieved through information fusion, physical quantity conversion, and post-processing with fully connected layers. Experimental results on the reconstruction of gas absorption spectra within the 3.7−4.8 μm band with 45 channels in real-world scenarios demonstrate that the proposed method achieves a peak signal-to-noise ratio (PSNR) of more than 28.159 dB and a spectral angle mapper (SAM) value of better than 0.053 rad. For a data cube with an image resolution of 320×256, the reconstruction time is approximately 0.65 seconds. This method effectively breaks through the technical bottleneck of high-precision MWIR spectral reconstruction, and it features both the interpretability of physics-driven models and the generalization capability of data-driven models. It provides a feasible technical path for MWIR spectral compressed sensing and exhibits significant potential for practical applications.

To address the low optical efficiency in the peripheral regions of large-scale solar power tower heliostat fields, this study proposes an overlapping layout optimization method and a multi-target aiming strategy for triple-tower solar thermal power plants. First, Particle Swarm Optimization (PSO) is utilized to determine the optimal configuration for a single-tower layout. These individual fields are then arranged, and the optimal overlapping triple-tower layout is established by refining the inter-tower distances. Finally, a multi-target aiming strategy is implemented for heliostats within the overlapping zones based on their instantaneous optical efficiency. By modeling the solar concentration process and comparing layout configurations, the results demonstrate that the annual average optical efficiency of the overlapping triple-tower field is 0.24% higher than that of the distributed counterpart. Furthermore, the overlapping arrangement is more compact, resulting in a significantly reduced land footprint.

To overcome the formidable challenges of suppressing laser frequency noise and clock noise in millihertz-band space-borne gravitational wave detection, as well as the inherent complexity and limitations of conventional second-generation Time-Delay Interferometry (TDI) schemes, this study proposes an innovative payload architecture and noise suppression strategy based on Space-borne Optical Clocks (SOCs). We first detail the core payload design, which replaces the traditional Ultra-Stable Oscillator (USO) on each spacecraft with an advanced SOC system. Subsequently, we introduce two synergistic noise suppression mechanisms: locking the laser strictly to atomic transition frequencies, and employing optical frequency combs (OFCs) to down-convert the optical clock frequency into a highly stable microwave clock signal. Drawing upon the stability parameters of state-of-the-art SOCs, the system's noise suppression performance across the target frequency band of 0.1 mHz to 1 Hz is comprehensively verified through both theoretical analysis and numerical simulations. The results demonstrate that the proposed scheme suppresses laser frequency noise and clock noise by two and three orders of magnitude in the millihertz band, respectively, ensuring that the residual noises remain well below the stringent noise floor required for the mission. Remarkably, this architecture enables the first-generation TDI technology to fully satisfy the mission requirements, thereby eliminating the need for additional complex clock-noise-removal algorithms. Consequently, while preserving high detection sensitivity, this scheme drastically enhances the simplicity and robustness of the data processing pipeline, and significantly relaxes the rigorous precision constraints typically imposed on inter-spacecraft ranging and clock synchronization. As SOC technology continues toward miniaturization, the proposed framework exhibits substantial application potential for future space-borne gravitational wave observatories.

Weak measurement technique based on weak-value amplification offers an effective method to detect the tiny spin splitting in the photonic spin Hall effect. However, its performance is constrained under conditions of strong coupling or near-orthogonality between the pre- and post-selected states. Based on differential interference theory, this work establishes a relation between the spin-dependent displacement and the amplified displacement for vortex beam with arbitrary topological charge under partial reflection at an air–glass interface. The relation remains valid even under strong-coupling conditions or when the pre- and post-selected states are nearly orthogonal, and is applicable for arbitrary incident linear polarizations. The corresponding characteristics of vortex beam reflected at an air–glass interface is systematically analyzed, and the influences of key parameters including the incident angle, topological charge, incident polarization state, post-selection angle, and propagation distance on the amplified displacement are elucidated. This study provides a valuable theoretical foundation for the applications of vortex beam in precision optical measurement and optical micromanipulation.

The microwave photonic filter based on weighted delay structure simultaneously leverages the advantages of photonic and radio-frequency components, featuring reconfigurability, low cost, and wide bandwidth, providing flexible and efficient signal processing capabilities in the microwave band. However, due to the complexity of the weighted delay structure, discrete optoelectronic components in the system can interfere with the weighted taps at different wavelengths—such as the envelope and gain competition of optical frequency combs, the gain non-uniformity and nonlinearity of EDFA, and the limited filtering bandwidth of modulators. These factors cause deviations in the weighted taps from their designed values, leading to distortion in the microwave filter. This paper proposes an end-to-end optimization approach by treating the microwave photonic filter as a black-box system. By monitoring the spectral shape (i.e., the weight values of each tap) of the final output in real time, the difference between the wavelength taps and the ideal taps is calculated and feedbacked to adjust the filtering coefficients of the waveshaper in real time, ensuring the output spectral weights remain in the designed state. Through this end-to-end optimization approach, we achieved a spectral reconstruction accuracy of 0.05dB and completed an RF low-pass filter with an out-of-band rejection ratio of up to 47dB.

Diffractive waveguides have emerged as a particularly promising solution for augmented reality (AR) near-eye display technologies. These waveguides are characterized by their light weight, wide field of view, and large eyebox. However, most commercially available AR waveguide simulation software has been developed by foreign companies, and there has been little advancement in domestic 3D visualization software for optical waveguide design and simulation. The present study is, to the best of our knowledge, the first to develop 3D visualization module for optical waveguide design and simulation based on ray-field tracing. Using this module, a two-dimensional exit-pupil-expansion diffractive waveguide has been designed, and a systematic design workflow is demonstrated. The workflow integrates k-domain analysis, automated layout generation of grating regions within the optical waveguide, waveguide optimization, and ray-field tracing simulations, thereby establishing a cohesive methodology for device development. The module extends beyond single-waveguide simulations to system-level analyses of near-eye displays, including micro-displays, micro-projectors, and human eye models. By bridging the microscopic and macroscopic scales, it enables holistic performance evaluation of AR optical systems, highlighting their capabilities and technical advantages. This module provides a robust and efficient platform for domestic optical engineers to advance the design and simulation of optical waveguides, thereby accelerating the industrialization and technological advancement of AR optics in China.