随着大数据时代的到来，空间光通信已被广泛应用于各种通信系统中，但随之而来的是容量瓶颈的挑战。基于光场频率、时间、偏振、横向空间模式等维度调控的信息编解码方法在解决容量问题方面展现了优异性能，但光场的纵向维度却未被应用于信息编解码。针对此问题，本文提出了一种基于电介质超表面的光场纵向维度信息编解码新方法，基于四原子结构的几何相位和传输相位联合调控，实现了透射场自旋相关的复振幅调控。同时，利用光学冻结波原理产生了轨道角动量模式叠加态的纵向可控变化，并验证了光场模态的纵向调控能够以指数级提升信道中的模态容量。纵向维度作为一个全新的编码自由度，有望进一步提高自由空间光通信性能。

The spin Hall effect of a light beam is essentially a product of circular birefringence but is rarely demonstrated. Here, we provide a scheme for initiating off-axis circular birefringence based on the spin-dependent wave vector bifurcation of Bessel beams via a single liquid crystal Pancharatnam–Berry phase element. The tilted Bessel beam shows a detectable photonic spin Hall effect. By introducing the nonlinear propagation trajectories, the spin Hall effect is greatly enhanced. More surprisingly, the two spin states exactly propagate along the scaled trajectories, enabling flexible control of the spin separation. This phenomenon is also applicable to other Bessel-like beams with nonlinear trajectories, which have been already reported.

表面等离激元因其极强的束缚光场能力，成为亚波长尺度下研究光与物质相互作用的理想平台，也是构建未来小型化、低功耗、高便携光电子器件的核心单元。更多维度、更加精确和灵活地调控等离激元的模式性质对推动其基础和应用研究至关重要。近年来，光场调控技术的发展，拓展了人们利用光场的维度，也赋予光场更强大的操控等离激元模式的能力。本文简述了矢量光场与等离激元模式作用的基本理论与物理机制，回顾了近年来矢量光场调控等离激元模式激发、耦合和远场辐射的研究进展，并介绍了相关研究在增强光谱、纳米颗粒光捕获、纳米位移传感等方面的应用。

We numerically demonstrate that the tight focusing of Bessel beams can generate focal fields with an ultra-long depth of focus (DOF). The ultra-long focal field can be controlled by appropriately regulating the order of the Bessel function and the polarization. An optical needle and an optical dark channel with nearly 100λ DOF are generated. The optical needle has a DOF of ∼104.9λ and a super-diffraction-limited focal spot with the size of 0.19λ2. The dark channel has a full-width at half-maximum of ∼0.346λ and a DOF of ∼103.8λ. Furthermore, the oscillating focal field with an ultra-long DOF can be also generated by merely changing the order of the input Bessel beam. Our results are expected to contribute to potential applications in optical tweezers, atom guidance and capture, and laser processing.

We demonstrate spectral-furcated vector solitons in normal-dispersion fiber lasers comprising a section of polarization-maintaining fiber. The spectrum of each orthogonal-polarized component is confined by the birefringence-related phase-matching principle, and the bicorn spectral structure corresponds to the zero-order sidebands of two vector modes. Due to the Hopf bifurcation effect, the vector soliton evolves into a breathing state at the higher pump level, accompanied by an extra set of sub-sidebands that continuously exchange energy with the zero-order sidebands. Simulation results fully reproduce experimental observations of the spectral furcation and soliton breathing, offering comprehensive insights into the pulse-shaping mechanism of the birefringence-managed soliton.

建立了环境温度对双层衍射元件衍射效率影响的数学模型，给出高衍射效率衍射元件的优化设计方法。通过选择宽温度范围内设计波长对，计算衍射元件微结构参数，确保双层衍射元件在基底材料确定的情况下仍具有高衍射效率，发现混合成像光学系统具有最佳像质。最后设计了一套含有此双层衍射元件的中波红外混合成像光学系统。结果表明，与传统设计相比，本文方法能够有效地改善混合成像光学系统的无热化设计像质，设计结果更好。

基于衍射元件的特殊成像性质，使用双层衍射元件进行双波段红外光学系统设计已成为研究热点。使用双层衍射元件能够有效提升宽波段的衍射效率，在简化系统结构的基础上提高像质。将红外成像系统设计为制冷型结构，能够消除背景噪声干扰，保证100%的冷光阑效率。基于带宽积分平均衍射效率最大化方法，设计了一款含有双层衍射元件的制冷型双波段红外光学成像系统，实现了在双波段红外和宽温度范围下的无热化设计。光学系统含有三片透镜，仅由两种材料组成，入瞳直径为80 mm，焦距为100 mm，F数为1.25，有效视场为6°，工作波段为3.7~4.8 μm和8.0~12.0 μm，工作环境温度为-40~60 ℃。分析结果表明，在整个温度范围内，在17 lp/mm截止频率处，双波段红外光学系统所有视场的调制传递函数分别高于0.78和0.59，同时双层衍射元件在红外双波段的带宽积分平均衍射效率分别为99.35%和98.73%，综合带宽积分平均衍射效率为99.04%。此光学系统的结构设计简单，成像质量好，在**和商业应用中具有一定优势。

We propose a chip-integratable cylindrical vector (CV) beam generator by integrating six plasmonic split ring resonators (SRRs) on a planar photonic crystal (PPC) cavity. The employed PPC cavity is formed by cutting six adjacent air holes in the PPC center, which could generate a CV beam with azimuthally symmetric polarizations. By further integrating six SRRs on the structure defects of the PPC cavity, the polarizations of the CV beam could be tailored by controlling the opening angles of the SRRs, e.g., from azimuthal to radial symmetry. The mechanism is governed by the coupling between the resonance modes in SRRs and PPC cavity, which modifies the far-field radiation of the resonance mode of the PPC cavity with the SRR as the nano-antenna. The integration of SRRs also increases the coupling of the generated CV beam with the free-space optics, such as an objective lens, promising its further applications in optical communication, optical tweezer, imaging, etc.