Monocular, stable, low-computation-cost, and high-precision stereo imaging has been a key focus in the fields of robotics, autonomous driving, and machine vision. However, the majority of current stereo imaging research tends to prioritize the stereoscopic effects while neglecting the importance of computational efficiency. This significantly impacts the deployment and application of stereo imaging in industrial settings. In this paper, we propose a stereo imaging scheme based on depth from defocus, integrating the latest advancements in optical systems to overcome the computational efficiency limitations of existing algorithms. By introducing aberration analysis of the optical system, we re-derive the principles of depth from defocus to enhance both the accuracy and range of stereo imaging. Experimental results validate the effectiveness of the proposed method and the accuracy of the precision calculations. Finally, we analyze the impact of optical system parameters on the relevant methods. Theoretical derivations reveal the relationships between spatial resolution, depth resolution, and the range of stereo imaging in depth from defocus approaches, providing theoretical guidance for the design and deployment of such methods in practical application scenarios.

Field-deflection optical elements play a significant role in various high-resolution and field-of-view (FOV) expandable optical systems. In our previous work, we proposed a self-achromatic double-faced grism (DFG) configuration capable of field deflection. In this paper, to effectively guide the design and fabrication of DFG diffractive microstructures, we analyze the diffraction process of light within the DFG based on scalar diffraction theory, establish a diffraction efficiency model for the DFG, and propose an optimization method to improve diffraction efficiency over all FOVs while minimizing diffraction efficiency variations across the waveband. Following this design approach, two DFGs for 3-5 mu m were specifically designed: one for a 4.4 degrees FOV with 1.6 degrees deflection, and the other for a 40 degrees FOV with 15 degrees deflection. Further optimization increased the bandwidth-integrated average diffraction efficiency (BIADE) to above 0.93 and reduced the diffraction efficiency variations across the waveband by 23.5% and 48%. And based on a tolerance analysis model, we performed tolerance analysis of the designed DFGs. The BIADE of both elements across all FOVs can exceed 0.86 after adding fabrication errors, maintaining a high diffraction efficiency. The results demonstrate that this method can effectively guide the design and manufacturing of diffractive microstructures.

Long wave infrared metalenses provide a promising route toward compact multispectral optical systems, including spaceborne imaging and sensing payloads. However, achromatic focusing at separated LWIR wavelength channels remains challenging because the required phase relation must be maintained together with sufficient dispersion control and optical throughput. Here, we propose a robust four-wavelength achromatic metalens operating at 8, 10, 12, and 14 μm based on a meta-atom library controlled by nanopillar radius and height. The library feasibility is evaluated before layout optimization to verify whether the required phase and dispersion responses are accessible within the selected unit cell space. By introducing nanopillar height as an additional degree of freedom, the library achieves a phase coverage ratio above 0.92 at all four wavelengths. The optimized metalens achieves a mean absolute focusing efficiency (AFE) of 69.5% with suppressed chromatic focal shift. Monte Carlo perturbation analysis and full device FDTD simulations further confirm the robustness and focusing stability of the design. This work provides a feasibility-driven strategy for robust multispectral LWIR achromatic metalenses.

Multispectral imaging systems capture spatial and spectral data simultaneously. Aperture segmentation reduces system size versus multi-lens designs, but lowers spatial resolution. Wide working band requires different lens counts per channel to correct chromatic aberration, increasing complexity. We propose a local high spatial resolution imaging method for segmented wide-spectral systems, using a main image plane and a spatial light modulator (SLM) that dynamically adjusts local aberration, enabling high spatial resolution observation of regions of interest. The system operates at 500-1600 nm (visible and near-infrared groups, each with four channels, total eight channels), with a 20 degrees field of view. Each exposure captures all four channels of either group. With SLM, the RMS radius of the selected field drops, up to about 50%. MTF differences between tangential and sagittal planes reduce, as does wave aberration. This design enables simultaneous overall and local target observation for complex environments.

This study proposes a dual-band, mid-wave infrared (MWIR) and long-wave infrared (LWIR) polarization-multiplexed optical system based on a metasurface. By employing matrix-based phase encoding technology, we pioneered the use of a dual-band polarization multiplexing architecture for parallel processing, achieving full-Stokes polarization detection. This system realized wavelength and polarization multiplexing across six axial focal planes and the off-axis focal points on each focal plane. The system also achieved a high transmittance of 85%; the average transmittance of this system exceeded 70% in the 3-12 mu m range. The focusing efficiency in the MWIR and LWIR is 71.1% and 62.5%, respectively, with polarization crosstalk below -25 dB. We used the inverse design method, shortening the design cycle by 80%. It provides a compact solution for infrared imaging, multispectral analysis, and biological tissue pathological detection.

Conventional snapshot-type polarization devices often suffer from inherent ohmic losses caused by the metal structure, resulting in low utilization of system light energy. This research proposes a dual-layer sandwich architecture metasurface that integrates polarization control and high light transmittance for the mid-wave infrared 3~5 μm band. The top metal polarization-selective structures and the bottom dielectric hemispherical anti-reflection (AR) array are integrated monolithically on the same substrate. Specifically, the numerical simulations predict a peak transmittance of 95% at 4.4 and 4.8 μm, while maintaining extinction ratios ranging from 81.8 dB to 84.3 dB. This enables high extinction ratio polarization splitting while significantly broadening the transmittance flux of the device. It breaks the inherent trade-off between “high extinction ratio” and “high transmittance” in polarization devices, providing a high signal-to-noise ratio hardware foundation for high temporal resolution detection.

Infrared focal plane arrays (IRFPAs) often suffer from spatiotemporal nonuniformity that persists after conventional two-point nonuniformity correction (NUC), especially under temperature drift and time-varying readout conditions. These residuals are typically structured, including column-group striping caused by shared column-end circuits and row-wise baseline/common-mode drift induced by row-scanning paths. We propose a structured, digital-twin-inspired detector-side refinement of two-point NUC that augments the bias term with interpretable low-dimensional components: a static column bias vector capturing group-correlated residuals and a row-related structured term consisting of a static row baseline and a frame-synchronous common-mode component with row-dependent sensitivity, while keeping the two-point gain/offset backbone unchanged. Rather than representing a full system-level digital twin of the infrared payload, the proposed framework serves as a detector-side virtual representation of dominant readout-induced structured residual states that can be estimated and updated from calibration data. Experiments on blackbody calibration data across multiple temperature points demonstrate that the column-related structured component significantly reduces group-wise column residuals, the row-related structured component suppresses time-varying row striping, and the combined method improves both column- and row-direction metrics consistently across temperatures.

Wide field of view (FOV), high resolution, and multispectral capabilities have long been pivotal parameters for optical instruments used in detection. From a biomimetic perspective, this paper proposes a practical method for designing a high-speed dual-channel off-axis reflective foveated imaging optical system. The structure of all reflectors enables the system to perform wide spectrum imaging. By employing a channel-select structure in conjunction with Digital Micromirror Device (DMD, a high-speed refresh device), the system achieves an integration and rapid switching between a wide FOV with a short focal length and a narrow FOV with a long focal length. Furthermore, emulating the central fovea imaging mechanism of the human eye and using the programmable function of DMD, the system simultaneously enables low-resolution imaging over a wide FOV and dynamic high-resolution imaging in local regions of interest. To verify the feasibility of this approach, a corresponding system was designed, with a 2x zoom ratio between the two channels. The system exhibits excellent imaging quality enabling pixel-level control over the foveated imaging region, and crosstalk between channels is effectively suppressed.

Current designs of optical super-oscillatory devices predominantly focus on the visible and near-infrared bands. However, for the detection of specific targets, the mid-wave infrared (MWIR) band also contains abundant valuable information. Applying optical super-oscillatory technology to the field of infrared detection is of significant research interest. This technology can overcome the resolution limitations inherent in conventional infrared focal-plane imaging systems, thereby enabling the detection and early warning of small infrared targets within localized fields of view. This paper proposes what we believe to be a novel approach for achieving far-field optical super-resolution in MWIR systems by employing an amplitude-type pupil filter. Based on this approach, a prototype of a long-focal-length MWIR imaging optical system is designed and fabricated. This prototype demonstrated a super-resolution factor of 1.195 at the focal plane. Both simulation results and proof-of-concept experiments verify the feasibility and effectiveness of the proposed MWIR super-oscillatory far-field super-resolution imaging scheme.

Field-deflecting optical elements play a crucial role in various high-resolution and field-expandable optical systems. However, for widely used prism-based field-deflecting optical elements, the issue of chromatic aberration correction under wide-field conditions remains unresolved. To solve this problem, we first propose a self-achromatic double-faced grism (DFG) configuration based on a single prism and establish a parametric design model for the DFG under wide-field self-achromatic conditions. Based on this model, an optical imaging system with a field deflection range of −3.6° to +0.8° operating in the 3–5 μm wavelength band was designed. The absolute residual chromatic aberration of the DFG element is less than 0.07 across all field points, and the MTF of the imaging system exceeds 0.2@33 lp/mm for all fields. The design results demonstrate that the proposed element can effectively achieve achromatic field deflection in wide-field optical systems.

In current visible light stealth technologies, camouflage and projection-based stealth techniques are commonly employed to blend the target into the background, achieving visual consistency when observed through a visible light camera. Although the camouflage target has the same color as the background, their spectral characteristics are inconsistent, making it easy to distinguish the target from the background by a multispectral camera. To address these problems, we propose an advanced optical spectral stealth technology based on multispectral composite projection. The proposed method employs a visible light spectrum sensing algorithm to calculate the most informative spectral bands of the target. Subsequently, an adaptive multispectral solution and modulation algorithm is used to adjust the projection spectrum of the target to ensure spectral consistency with the background. A multispectral composite projection system is then used to project the modulated spectrum onto the scene. Finally, a spectral reflectance matching algorithm adjusts the projection brightness of the target, ensuring both spectral and intensity consistency between the target and the background. Experimental results demonstrate the proposed method achieves effective stealth across different environments and can successfully resist detection by multispectral cameras. The proposed method is applicable to the concealment and protection of important targets.

Due to the superior ability to edit the characteristics of light, metasurface has substantial potential in information storage and encryption. As the information carrier, nanoprinting metasurfaces have gained great attention because they can achieve multichannel image encryption in the near-field by rotating the orientation of the meta-atom. However, most existing studies have primarily focused on binary image encryption, which substantially constrains the information entropy and data dimensionality of encrypted content. To overcome this drawback, an optical encoding method using the interference of transmitted polarized light is proposed. Theoretical analysis and experimental results indicate that the nanoprinting metasurface fabricated based on the proposed encoding method can achieve dual-channel grayscale display and encryption in the near field. This study demonstrates a breakthrough enhancement in the information-bearing capacity of nanoprinted metasurfaces, thereby establishing a novel paradigm for high-throughput optical encryption.

In current multispectral projection technologies, the colors projected by multispectral projection systems based on filter wheels depend on the characteristics of the light source and filters used. Although increasing the number of color channels, these systems still cannot reproduce arbitrary spectra. On the other hand, multispectral projection systems using multiple stacked projection devices require precise geometric calibration between devices, increasing the system’s size and operational complexity. To address these problems, we propose an advanced multispectral composite projection system based on novel spectral time-division encoding technology. This system uses a beam shaping system to shape a visible full-spectrum light source, then employs a grating to split the light into different wavelengths. Finally, the high dynamic response of a DMD and a FSM is used to stack the spectra in the time domain, achieving the effect of multispectral composite projection. The experiments verify the effectiveness of the proposed multispectral composite projection system, demonstrating an expansion of the color gamut. The proposed system in this paper has potential applications in fields such as multispectral projection camouflage and wide-gamut projection.

Freeform surfaces play a critical role in complex light-field modulation. However, traditional geometric mapping and standard optimization methods are limited by computational cost and convergence instability in large-scale ray tracing and complex surface modeling. This paper introduces DiffRayFlow, which integrates discrete optimal transport (OT), end-to-end differentiable ray tracing (DRT), and an adaptive multi-scale strategy. OT provides a global, energy-conserving geometric map. Differentiable tracing parameterizes the surface using the finite difference method (FDM) and constructs a differentiable link from height parameters to target landing points. The multi-scale approach, combined with early stopping, enhances efficiency and stability. For typical tasks involving over a million rays, the core heightmap optimization is usually completed within 20 s. The method can output standard Computer-Aided Design (CAD) data for rapid prototyping and physical validation. Ablation studies show that the multi-scale strategy is key to achieving high-precision convergence, while the early stopping mechanism can reduce optimization time by about 40% without sacrificing reconstruction quality. DiffRayFlow provides an efficient engineering path for interactive design and large-scale customization.

This publisher's note reports corrections to Appl. Opt.64, 6803 (2025)APOPAI0003-693510.1364/AO.564737.

Foveal vision, commonly observed in animal vision systems, enabling organisms to monitor a wide field of view while simultaneously capturing high-resolution images of specific local areas. This mechanism significantly enhances the efficiency of target search, recognition, and tracking under resource-constrained conditions, making it an economical visual strategy. Inspired by foveal vision, this paper proposes a dynamic foveal computational imaging method based on frequency domain compression. Through a carefully designed optical architecture, the two channels of the dual channel system are configured to share a common image plane. The system's point spread function is engineered using a genetic algorithm, allowing the mixed image captured by the system to be decomposed into individual channel images via compressive sensing theory. As a result, the system's information throughput can be doubled without increasing its bandwidth. To further enhance the efficiency of target search and tracking, the foveal channel is equipped with a scanning mirror that enables high-resolution imaging of arbitrary regions within the wide field of view channel. We present a design example of the proposed foveal computational imaging system and develop an image reconstruction algorithm based on the alternating direction method of multipliers. A proof-of-concept experiment is conducted to demonstrate the system's foveal imaging capabilities, and the experimental results verify that this method has promising potential for development in fields such as space remote sensing, target recognition, and tracking.

In recent years, learning-based underwater polarimetric imaging models have undergone rapid expansion. Unfortunately, the majority of learning-based models have limitations in feature extraction and fail to make full use of frequency domain features. To further improve restoration capability, we present a dual-channel encoding model in the spatial and frequency domains for underwater polarimetric imaging. First, to effectively restore the high- and low-frequency features of hazy polarization images, we utilize two subnetworks to decompose the images into high- and low-frequency components, enabling the network to recover the hazy polarization images on the two feature components. Specifically, we employ a lightweight encoder–decoder architecture to restore the low-frequency feature components. Meanwhile, for the high-frequency feature components, we introduce a well-designed high-frequency aggregation component, which recovers the high-frequency features of the current region by referring to neighboring feature distributions that are not completely corrupted by backscattered light. Second, we introduce an additional spatial domain network integrating an active polarization imaging model proposed in our previous work to directly restore spatial features. Lastly, the results from the frequency and spatial domain networks are fused to reconstruct clear images. Experimental results on the established underwater polarization dataset verify that our method, to our knowledge, outperforms other advanced methods.