Light field 3D display technology is considered a revolutionary technology to address the critical visual fatigue issues in the existing 3D displays. Tabletop light field 3D display provides a brand-new display form that satisfies multi-user shared viewing and collaborative works, and it is poised to become a potential alternative to the traditional wall and portable display forms. However, a large radial viewing angle and correct radial perspective and parallax are still out of reach for most current tabletop light field 3D displays due to the limited amount of spatial information. To address the viewing angle and perspective issues, a novel integral imaging-based tabletop light field 3D display with a simple flat-panel structure is proposed and developed by applying a compound lens array, two spliced 8K liquid crystal display panels, and a light shaping diffuser screen. The compound lens array is designed to be composed of multiple three-piece compound lens units by employing a reverse design scheme, which greatly extends the radial viewing angle in the case of a limited amount of spatial information and balances other important 3D display parameters. The proposed display has a radial viewing angle of 68.7° in a large display size of 43.5 inches, which is larger than the conventional tabletop light field 3D displays. The radial perspective and parallax are correct, and high-resolution 3D images can be reproduced in large radial viewing positions. We envision that this proposed display opens up possibility for redefining the display forms of consumer electronics.

由于集成成像显示系统具有有限的景深，在微图像阵列获取与生成过程中，要考虑3D图像的重建深度，确保再现的3D图像在集成成像显示系统的景深范围内。当3D图像的重建深度与显示系统景深不适配时，需要重新调节拍摄参数以清晰地显示3D图像。为了避免对目标三维场景进行重新采集，提高微图像阵列生成效率，本文提出一种不同重建深度的微图像阵列生成方法。该方法通过调整图像元节距、调节相邻图像元间的视差值来改变光场的采样间隔，使微图像阵列可以适配不同景深的3D显示系统，提升集成成像微图像阵列的实用性。实验结果表明，该方法能实现不同深度的3D图像重建，验证了所提方法的正确性和可行性。

随着3D显示被应用到**医疗等尖端领域，高分辨率的3D图像变得尤为重要。然而，集成成像的3D显示性能受制于2D显示屏的分辨率。为了突破2D显示屏的分辨率限制，本文提出了基于回返器和反射偏振片的集成成像3D显示装置。该装置将显示器上的微图像阵列（elemental image array，EIA）通过反射型偏振片分离成偏振方向正交的两束光线，回返器、四分之一波片和反射型偏振片分别将两束偏振光反射，并沿着像素的对角线方向以2/2个像素错位叠加，形成一个具有更小像素单元和更多像素数量的高分辨率EIA。根据两个偏振EIA和叠加的高分辨率EIA之间的像素索引关系，反向计算出偏振EIA的像素值。实验结果表明，该系统不仅可以重构出高分辨率的3D图像，还减弱了像素间的黑网格。

Security is one of the key issues in communications, but it has not attracted much attention in the field of underwater wireless optical communication (UWOC). This Letter proposes a UWOC encryption scheme with orthogonal frequency division multiplexing (OFDM) modulation, based on the three-layer chaotic encryption and chaotic discrete Fourier transform (DFT) precoding. The three-layer chaotic encryption processes are bit stream diffusion, in-phase/quadrature encryption, and time-frequency scrambling. With multi-fold data encryption, the scheme can create a keyspace of 9.7×10179, effectively resisting brute force attacks and chosen-plaintext attacks. A 3 Gbit/s encrypted OFDM signal is successfully transmitted over a 7 m water channel.

Due to the proliferation of underwater vehicles and sensors, underwater wireless optical communication (UWOC) is a key enabler for ocean exploration with a strong reliance on short-range bandwidth-intensive communications. A stable optical link is of primary importance for UWOC. A compact, low-power, and low-cost acquisition, pointing, and tracking (APT) system is proposed and experimentally demonstrated to realign the optical link within 0.04 s, even when the UWOC transmitter and receiver are in relative motion. The system successfully achieves rapid auto-alignment through a 4 m tap water channel with a relatively large number of bubbles. Furthermore, the required minimum illumination value is measured to be as low as 7.1 lx, implying that the proposed APT scheme is robust to dim underwater environments. Meanwhile, mobility experiments are performed to verify the performance of the APT system. The proposed system can rapidly and automatically align moving targets in complex and unstable underwater environments, which can potentially boost the practical applications of UWOC.