二维材料，具有原子厚度，以其独特的物理、化学性质，吸引了广大研究人员的关注，成为了众多研究领域（如物理、材料、电子、光电子和化学等）的明星材料。因二维材料具有较高的载流子迁移率、强的光-物质相互作用、电/光学性质各向异性等，使其在光电子领域具有光明的应用前景。其中，窄带隙二维材料，如黑磷、黑磷砷等，在红外光电探测器中表现出巨大的应用潜力，成为了红外探测领域的新宠。文中将对二维材料在红外探测器中的应用，特别是光子型光电探测器的最新进展进行介绍。首先对二维材料的背景进行介绍；然后介绍表征光电探测器的关键参数；接着介绍二维材料在红外探测器中的最新进展，分别展示了单二维材料红外探测器、异质结红外探测器和光波导红外探测器方面的进展；最后对二维材料在红外探测器中的应用进行展望。

基于空间光调制器的无掩膜光刻是光刻技术重要发展方向之一。近年来，随着数字微镜器件芯片集成度与性能的提高，数字微镜器件无掩膜光刻成为一种主要的数字光刻技术。由于可灰度调制的光反射式“数字掩膜”替代了传统光刻中使用的预制物理光掩膜版，该技术极大地简化了光刻制版流程，提高了光刻的灵活性，广泛应用于平面微纳器件、超材料、微流控器件、组织生物研究等领域。从数字无掩膜光刻原理出发，简要介绍了典型匀光照明系统结构与微缩投影系统结构，进而介绍了面向平面光刻的空间分辨率增强技术、灰度光刻技术以及三维微立体光刻技术的进展。最后，列举了几类典型的数字无掩膜光刻应用，并对其发展方向进行了展望。

Initiated by graphene, two-dimensional (2D) layered materials have attracted much attention owing to their novel layer-number-dependent physical and chemical properties. To fully utilize those properties, a fast and accurate determination of their layer number is the priority. Compared with conventional structural characterization tools, including atomic force microscopy, scanning electron microscopy, and transmission electron microscopy, the optical characterization methods such as optical contrast, Raman spectroscopy, photoluminescence, multiphoton imaging, and hyperspectral imaging have the distinctive advantages of a high-throughput and nondestructive examination. Here, taking the most studied 2D materials like graphene, MoS2, and black phosphorus as examples, we summarize the principles and applications of those optical characterization methods. The comparison of those methods may help us to select proper ones in a cost-effective way.

We report an erbium-doped fiber laser passively Q-switched by a few-layer molybdenum disulfide (MoS2) saturable absorber (SA). The few-layer MoS2 is grown by the chemical vapor deposition method and transferred onto the end-face of a fiber connector to form a fiber-compatible MoS2 SA. The laser cavity is constructed by using a three-port optical circulator and a fiber Bragg grating (FBG) as the two end-mirrors. Stable Q-switched pulses are obtained with a pulse duration of 1.92 μs at 1560.5 nm. By increasing the pump power from 42 to 204 mW, the pulse repetition rate can be widely changed from 28.6 to 114.8 kHz. Passive Q-switching operations with discrete lasing wavelengths ranging from 1529.8 to 1570.1 nm are also investigated by using FBGs with different central wavelengths. This work demonstrates that few-layer MoS2 can serve as a promising SA for wideband-tunable Q-switching laser operation.