随着红外探测技术手段的多样化发展，红外隐身技术的需求日益迫切。由于传统的红外隐身技术面临着多途径目标探测和多功能兼容的严峻挑战，因此研究光学微纳结构红外隐身技术有着十分重要的意义。基于局域共振机制的亚波长尺度的光学微纳结构，极大地丰富了人们对光的传输行为的调控。在红外隐身技术领域，光学微纳结构可以针对红外辐射特性进行材料和结构的精细化设计，从而满足理想红外隐身发射光谱的需求，为发展更加多光谱、多功能、自适应的红外隐身技术提供全新的解决方案。文中围绕红外隐身技术的相关研究，首先介绍了多层薄膜吸收体、金属表面等离子激元、基于相变材料薄膜可调吸收体、智能化设计光学微纳结构实现光谱响应的基本原理，在此基础上，重点回顾了近年来基于光学微纳结构的红外隐身技术新特点，包括多光谱红外隐身技术、多功能红外隐身技术、自适应红外隐身技术的发展现状。最后，梳理了光学微纳结构红外隐身技术所存在的不足及面临的困难并对未来的研究方向和发展趋势进行了展望。

报道了高功率、高光束质量的垂直腔面发射半导体激光器(VCSEL)侧泵的Nd:YAG激光振荡器。从VCSEL泵浦源的主动冷却的热沉结构出发，设计了5个227 W的VCSEL线阵，并且通过优化侧面泵浦大口径激光棒的结构，研制成了具备480 W输出能力的棒状激光模块，相应的光-光效率为49.7%。在此基础上，设计了一种高功率、高光束质量的VCSEL侧面泵浦棒状Nd:YAG激光振荡器。腔内插入望远镜光学元件，并通过优化各光学元件的参数使其工作在热近非稳区域，以达到增大基横模体积和抑制高阶横模目的。最终，获得114 W的输出功率，相应的平均光束质量因子M²为1.42。由于VCSEL具备优秀的波长-温度稳定性，这种高功率、高光束质量的VCSEL泵浦的固体激光器在工业、空间等领域，具有极为广阔的应用前景。

In order to meet the practical needs of all-fiber conductivity-temperature-depth sensors with high sensitivity, compact structure, and easy packaging, this Letter uses a microfiber coupler combined with fiber loop (MCFL) reflective photonic device to conduct salinity, temperature, and deep sensing experiments. These MCFLs’ dynamic range and resolution of salinity, temperature, and depth can meet the requirements of actual marine environment monitoring. This structure opens up a new design idea for the practical research of microfiber coupler-based marine environmental parameter sensors.

An all-optical intensity modulator based on an optical microfiber coupler (OMC) is presented. The modulator works at 1550 nm wavelength and is modulated directly by heating the coupling region with 980 nm pump light injected through the coupling port of the OMC. The OMC is controlled to have at least a 30 mm long coupling region with diameter smaller than 8 μm, and the uniform waist region diameter is about 3 μm. This is helpful to ensure the optical modulation function based on the light induced thermal effect in the coupling region, while pump light is injected. The modulation response is measured to show good linearity when the 980 nm pump light has a lower intensity (with power below 2.5 mW), which proves that the OMC acts as an all-optical modulator. The bandwidth of the modulator can be at 0.2–50 kHz with the average power of the intensity-modulated pump light about 2 mW, which can be further improved by optimizing the design of the coupler. The demonstrated modulator may have potential value for the application in an all-optical integration system.

An integrated, tunable spectrometer based on a silicon-on-sapphire platform is designed at wavelengths of 2.29–2.35 μm. Its pivotal component is a 4.7 μm-radius ring resonator on a graphene monolayer. Its full width at half-maximum and free spectral range are ～1.5 and ～45 nm, respectively, as found through a numerical simulation and theoretical computation. Sixteen characteristic peaks are obtained by tuning the Fermi level of graphene. The gap between the ring and waveguides is increased by 0.5 μm to increase the resolution, and though this can drastically reduce the transmission rate, an upper sapphire layer maintains light to the drop port.

A novel and simple polarization independent grating couplers is designed and analyzed here, in which the TE polarization and the TM polarization light can be simultaneously coupled into a silicon waveguide along the same direction with high coupling efficiency. For the polarization-insensitive grating coupler, the coupling efficiencies of two orthogonal polarizations light are more than 60% at 1550 nm wavelength based on our optimized design parameters including grating period, etching height, filling factor, and so on. For TE mode the maximum efficiency is ～72% with more than 30 nm 1 dB bandwidth, simultaneously, for TM mode the maximum efficiency is 75.15% with 40 nm 1 dB bandwidth. Their corresponding wavelength difference between two polarizations’ coupling peaks is demonstrated to be 35 nm. Polarization independent grating coupler designed here can be widely used in optical communication and optical information processing.