基于液晶的气体传感器是一个新兴的研究领域。液晶本身具有化学多样性、可逆的分子排列和固有的自组装能力，可以满足传感器高灵敏度、快速响应、低能耗和选择性等要求。随着相关研究的深入，液晶气体传感方法也不断被完善。本文回顾了近几年基于液晶的气体传感技术，讨论了现有液晶气体传感技术的检测方法，主要包括向列相液晶的气体检测方法和胆甾相液晶的气体传感方法。向列相液晶的气体传感包括功能化基板的液晶膜传感、特性几何形貌的液晶传感和液晶液滴传感方法。胆甾相液晶的气体传感主要包括聚合物胆甾相液晶膜的气体传感、液晶液滴传感、基于光纤的气体检测以及纤维素气体传感。最后对液晶气体传感的应用和发展进行了阐述。

为了获取爆炸波模拟装置出口处冲击波的演化过程和流场形态，更好地控制爆炸波模拟装置的加载波形，从而满足对**装备的加载要求，开展了爆炸冲击波的可视化图像研究。利用反射式纹影成像原理，通过高速CCD成像单元结合一系列光学元件，设计了基于激光光源的高速纹影测量系统，实现了爆炸波的图像演变过程测量，并通过外部冲击波压力传感器进行了对比分析。研究表明，通过该纹影系统获取的爆炸冲击波阵面数量与冲击波压力传感器所测结果吻合，并且获取了冲击波、反射波的图像形态以及形成演化过程，同时通过多个冲击波阵面的图像数据获取了爆炸冲击波的速度信息。该结果为爆炸波的有效加载以及更好地理解冲击波压力的形成和演化规律提供了新的技术途径和分析基础。

Understanding detailed avalanche mechanisms is critical for design optimization of avalanche photodiodes (APDs). In this work, avalanche characteristics and single photon counting performance of 4H-SiC n-i-p and p-i-n APDs are compared. By studying the evolution of breakdown voltage as a function of incident light wavelength, it is confirmed that at the deep ultraviolet (UV) wavelength region the avalanche events in 4H-SiC n-i-p APDs are mainly induced by hole-initiated ionization, while electron-initiated ionization is the main cause of avalanche breakdown in 4H-SiC p-i-n APDs. Meanwhile, at the same dark count rate, the single photon counting efficiency of n-i-p APDs is considerably higher than that of p-i-n APDs. The higher performance of n-i-p APDs can be explained by the larger impact ionization coefficient of holes in 4H-SiC. In addition, this is the first time, to the best of our knowledge, to report single photon detection performance of vertical 4H-SiC n-i-p-n APDs.

三维成像激光雷达因获取信息丰富、抗干扰能力强、分辨率高等优势已广泛应用于地貌勘测、自动驾驶、智能交通、视觉跟踪等**与民用领域。随着雪崩光电二极管（APD）探测器件的发展与三维成像体制的多样化(例如：微机电系统扫描、相控阵、闪光等)，激光雷达性能较早期已得到大幅提升。立足于军民领域对激光雷达的新需求，迫切需求新方法、新体制进一步提升三维成像的综合性能。首先从APD三维成像激光雷达的发射单元、接收单元、算法单元（数据处理单元）三方面关键技术展开分析。然后，以载荷应用需求对三维成像激光雷达进行了分类阐述与讨论，重点以车载环境感知为例深入讨论了现有激光雷达的应用现状与军民应用所面临的难点问题。基于APD器件的三维成像方法多元化发展，讨论了两种适用于APD器件的新型三维成像方法（异构变分辨率与鬼成像）。最后，在分析三维成像激光雷达研究现状的基础上，总结了三维成像激光雷达正朝着大视场、高分辨、高精度、实时性、模块化、智能化的方向发展，为进一步研究高性能三维成像激光雷达奠定基础。

4H-SiC single photon counting avalanche photodiodes (SPADs) are prior devices for weak ultraviolet (UV) signal detection with the advantages of small size, low leakage current, high avalanche multiplication gain, and high quantum efficiency, which benefit from the large bandgap energy, high carrier drift velocity and excellent physical stability of 4H-SiC semiconductor material. UV detectors are widely used in many key applications, such as missile plume detection, corona discharge, UV astronomy, and biological and chemical agent detection. In this paper, we will describe basic concepts and review recent results on device design, process development, and basic characterizations of 4H-SiC avalanche photodiodes. Several promising device structures and uniformity of avalanche multiplication are discussed, which are important for achieving high performance of 4H-SiC UV SPADs.

In this work, a GaN p-i-n diode based on Mg ion implantation for visible-blind UV detection is demonstrated. With an optimized implantation and annealing process, a p-GaN layer and corresponding GaN p-i-n photodiode are achieved via Mg implantation. As revealed in the UV detection characterizations, these diodes exhibit a sharp wavelength cutoff at 365 nm, high UV/visible rejection ratio of 1.2×104, and high photoresponsivity of 0.35 A/W, and are proved to be comparable with commercially available GaN p-n photodiodes. Additionally, a localized states-related gain mechanism is systematically investigated, and a relevant physics model of electric-field-assisted photocarrier hopping is proposed. The demonstrated Mg ion-implantation-based approach is believed to be an applicable and CMOS-process-compatible technology for GaN-based p-i-n photodiodes.