硫属非线性光学晶体的研究进展

Research Progress on Nonlinear Optical Crystals in the Chalcogenide System

现阶段,非线性光学晶体材料成为红外激光技术发展的重要媒介。硫属化合物具有大的非线性光学系数和宽的红外透过范围,成为目前探索红外非线性光学晶体的主要体系,例如商业化的硫镓银和硒镓银。但商业化的晶体具有低的抗激光损伤阈值等问题,限制了其应用范围。因此,探索具有宽带隙和大倍频的硫属红外非线性光学晶体成为研发的热点。目前,行之有效的方法是通过调控晶体结构来改善材料性能,主要有以下几种设计策略:(1)结构中引入碱金属/碱土金属阳离子调控带隙;(2)引入含d^(10)构型的IIB过渡金属为中心的四面体作为非线性活性基元;(3)复合阴离子组合(氧/硫或卤素/硫)调控材料性能。本文主要总结了上述3种方法的设计思路,以及对应体系材料的晶体结构-性能关系,为未来在硫属体系中设计新材料提供参考。

Recently, nonlinear optical(NLO) crystals are the important media for the development of infrared(IR) laser technology. Chalcogenides exhibiting the large NLO coefficients and wide IR transmission ranges have become the main system for the exploration of new IR NLO crystals, such as commercial Ag GaS_(2)and Ag GaSe2. However, commercial crystals possess the low laser damage thresholds(LDTs) that further limit their wide application regions. Thus, exploration of new IR NLO chalcogenides with wide bandgaps and large NLO effects has become the research hotspot. Recent effective method is to improve the performances through the regulation of crystal structures that includes the following methods:(1)introducing the alkali or alkaline earth metals into structures to regulate the optical bandgaps;(2)incorporation of IIB cations with d^(10) configuration-centered tetrahedra as NLO active units;(3)mixed-anions(O/S or halogen/S) regulating the material performances. In this paper, we have summarized the above-mentioned design ideas and the inherent structure-performance relationship in chalcogenides, which offers the good guidance for future design of new materials in the chalcogenide system.