对二阶红外非线性光学晶体材料的研究是当前激光及非线性光学领域研究的重点、难点和热点之一。由于满足应用需求的材料比较缺乏, 很有必要从源头上探索潜在的新型红外非线性光学晶体材料。硫属化合物和卤化物是红外非线性光学晶体新材料探索的主要体系, 前者一般表现出大的倍频效应和宽的红外窗口, 后者则多具有大的光学带隙, 即高的抗激光损伤阈值。结合两者的优势, 有望获得综合非线性光学性能优异的新材料。在此背景下, 本文综述了近期硫属卤化物红外非线性光学晶体材料的研究现状, 包括含S8单元的卤化物、包盐硫属卤化物和钡基硫属卤化物。这些硫属卤化物的粉末样品大都表现出优异的非线性光学性能。最后, 本文讨论了该方向未来研究的机会和重点。

The study of second-order nonlinear optical crystalline materials in the infrared region is one of the important, difficult, and hot topics in the fields of lasers and nonlinear optics. As the available ones are far from the market’s requirements, it is necessary to explore novel infrared nonlinear optical materials from the origin. Chalcogenides and halides are the most important candidates for infrared nonlinear optical materials. Chalcogenides usually present large second-harmonic generation effects and wide infrared windows, and halides usually have large optical band gaps, namely, high laser-induced damage thresholds. Combining their advantages, it is possible to obtain new infrared nonlinear optical materials with desirable properties. Based on this background, this work summarizes the recent status and progress on chalcohalide-type infrared nonlinear optical materials, including halides containing S8 unit, salt-inclusion chalcohalides, and Ba-based chalcohalides. Most of these chalcohalides powder samples exhibit nice NLO properties. The opportunity and importance of the future investigation on this topic are also proposed.