LBO晶体用于宽带激光谐波转换的基本特性  

BASICP ROPERTIES OF LBO RELATEDTO HIGH EFFICIENCY FREQUENCY CONVERSION OF BROADBAND LASER

作　　者：朱宝强[1] 钱列加[1] 张筑虹[1] 詹庭宇[1] 范滇元[1] 

机构地区：[1]中国科学院上海光学精密机械研究所

出　　处：《强激光与粒子束》1995年第1期95-100,共6页High Power Laser and Particle Beams

基　　金：上海市科委启明星计算和国家863共同支持

摘　　要：实现宽带高功率钕玻璃激光高效谐波转换的关键在于选择合适的非线性晶体和技术。文中给出了波长为１．０５４μｍ的基波光脉冲在ＬＢＯ晶体中的各类倍频及三倍频相位匹配，着重分析了ＬＢＯ的光谱接受范围和角度接受范围。结果表明，采用成熟的谐波转换技术，选用ＬＢＯ晶体，可实现ｌｎｍ左右的宽带高功率激光的高效三倍频转换。AbstractHigh power short wavelength broad-band laser has a lot of advantages for plasma experi- ments,such as increasing the absorption,improving target illumination uniformity and so on. Traditional third harmonic conversion scheme with KDP,however,can only be used for laserbandwidth less than 0.2nm. Therefore, to develop harmonic conversion techniques on broad- bandlaser is very important for ICF and x- ray laser research.For this purpose, new conversionschemes such as angular spectral dispersion(ASD)and crystal quadrature have been proposed. Based on our calculated results of the spectral and angular acceptanee for LBO crystal,inthis paper we have proposed to use LBO in traditional conversion scheme for efficientbroad- band laser harmonic conversion. We have studied all the phase- matching possibilities for frequency doubling and triplingbased on Sellmeier's equation. In our calculation,only the phase- matchings in principal planesare considered, since their large nonlinear coefficients.We have found that type Ⅰdoubling andtripling are only possible in xy plane,while typeⅡdoubling and tripling are in yz plane asshown in Table 3.By numericddl calculations of coupled wave equations,we found that only 4mmthickness is required for LBO when fundamental intensity is around 1.5GW/cm￣2,while 14mmthickness required for KDP crystal.The s pectral and angular acceptance for all interactions in4mm thick LBO at 1.054μm are calculated as shown in Table 5.the values for KDP are alsogiven as comparisons.As a md,in result,tripling spectral acceptance of LBO are much larger thanthose of KDP,efficient tripling can be achieved for bandwidth of about Inm in traditionaltripling scheme with LBO crystal.

关 键 词：LBO晶体 激光谐波转换 宽带 特性 

分 类 号：TN241[电子电信—物理电子学] O734.1[理学—晶体学]