摘要
红外激光变频技术急需新型的具有优良性能的非线性光学晶体,但获得能够实现大倍频和高激光损伤阈值平衡的新型红外非线性光学晶体依然是巨大的挑战,进一步的工作仍是科研工作者的研究热点.本文通过高温溶液法将高正电性的碱金属锂,碱土金属钡以及无机半导体硅与硒熔合高温反应得到了一种新型红外非线性光学晶体Li2Ba Si Se4,并获得了其光学性质的实验数据.经过漫反射数据转化得到的光学带隙实验值为2.47e V,2.09μm光源下的倍频效应与商业化使用的AgGaS2相当,约为KH2PO4(KDP)的30倍.第一性原理计算还分析了它的能带结构、态密度分布等.
Nonlinear optical(NLO) materials as important frequency-conversion devices in solid state lasers, have attracted unprecedented attentions in laser science and technology. In infrared(IR) region, NLO materials display more important roles in view of critical application prospect including laser guidance, resource exploration and long-distance laser communication etc. AgGaS2, AgGaSe2 and ZnGeP2 are selected as the commercial IR NLO materials, but they exihibit low laser damage thresholds(LDT) induced by their small bandgaps, which limit their further applications in high energy laser systems. Therefore, it is still a big challenge to obtain new IR NLO materials, which could balance the demand of large second-harmonic generation(SHG) and high laser damage threshold. As a NLO material, the non-centrosymmetrical structure is the prerequisite condition, and mix-metal chalcogenides have attracted much attention since their structures exhibit a variety of acentric units arising from the combination of different center metals, which show different sizes, coordination preferences, and packing characteristics. Previous investigations indicate that the introduction of alkali and alkali earth metals is good for obtaining large band gap because they may avoid the d-d and f-f electron transition like popular LiGaS2, BaGa4 S7 etc. Moreover, compared with sulfides, selenides produce larger SHG responses. Therefore, in this work, in aim at the balanced optical properties, we selected electricity-positive alkali metal Li, alkali earth metal Ba, silicon in IVA group and selenium as the raw materials. Through high temperature flux method, we have obtained a metal-mixed selenide Li2 Ba Si Se4. The raw materials are weighted with the molar ratio of 2:1:1:4, and then loaded into the graphite crucible, finally sealed in a silicon tube under ethane-oxygen flame. The tube is put in a program-computed furnace with the temperature program as blow:(1) heat from room temperature to 190°C in 3 h and keep at this temperature for 300 min;(2) hea
作者
李广卯
武奎
潘世烈
Guangmao Li;Kui Wu;Shilie Pan(Key Laboratory of Functional Materials and Devices for Special Environments,Xinjiang Key Laboratory of Electronic Information Materials and Devices,Xinjiang Technical Institute of Physics & Chemistry,Chinese Academy of Sciences,Urumqi 830011,China)
出处
《科学通报》
EI
CAS
CSCD
北大核心
2019年第16期1671-1678,共8页
Chinese Science Bulletin
关键词
红外
非线性
倍频效应
晶体
infrared
nonlinear optical
second-harmonic generation
crystal
