掺氧化镁铌酸锂晶体中高强度近红外飞秒激光脉冲线性电光效应  

Linear Electro-Optic Effect of Near-Infrared Femtosecond Laser Pulses with High Intensity in MgO…LiNbO_3 Crystal

作　　者：钟东洲[1,2] 佘卫龙[1] 

机构地区：[1]中山大学光电子材料与技术国家重点实验室,广东广州510275 [2]五邑大学信息工程学院,广东江门529020

出　　处：《激光与光电子学进展》2012年第7期167-174,共8页Laser & Optoelectronics Progress

基　　金：国家自然科学基金(90921009)资助课题

摘　　要：数值研究了掺氧化镁铌酸锂晶体中高强度近红外飞秒激光脉冲的线性电光效应。研究结果发现,当在垂直于晶体光轴的方向上施加一定外电场使光脉冲实现最强的电光耦合时,输出脉宽在正常色散区随着输入光强的增大而增大;而在较强反常色散区,输出脉宽随着输入光强增大而减小。对中心波长λ0=1.6335μm的光脉冲,线性电光效应可使输出脉宽产生压缩。当输入脉宽T0=5fs和光强I0=20GW/cm2时,最小输出脉宽为输入脉宽T0的0.76倍。而当T0>5fs时,最小输出脉宽小于0.76T0。若在晶体光轴方向上施加另一个电场对光脉冲进行相位调制,则最小输出脉宽的光脉冲中心波长发生蓝移或红移;随着外电场的增大,蓝移或红移量相应增大。The linear electro-optic（EO） effect of near-infrared femtosecond laser pulses with high intensity in MgO：LiNbO3 crystal is numerically investigated. It is found that,if an external electric field is applied along the direction perpendicular to the optical axis of crystal and is set at the optimization value of EO effect,a high input intensity will result in the broadening of output pulses in normal dispersion region.And in abnormal dispersion region,the output durations become narrower when the input light intensity becomes higher.For the light pulse with central wavelength at λ 0=1.6335 μ m,the output durations can be compressed by this EO effect.For example,with the input pulse duration T0=5 fs and intensity I0=20 GW/cm2 fixed,the minimum output duration is 0.76 T0.And for T0〉5 fs,the minimum output duration is less than 0.76 T0.If another external electric field is applied along the direction of optical axis of crystal to modulate the phase of light pulse,the central wavelength corresponding to the minimum pulse duration will make a blue or red shift and the shift becomes large with the increase of applied electric field.

关 键 词：光电子学 掺氧化镁铌酸锂晶体 飞秒激光脉冲线性电光效应 自相位调制 交叉相位调制 光脉冲压缩 

分 类 号：O436.4[机械工程—光学工程]