掺氧化镁铌酸锂晶体的损伤阈值分析  

Analysis of Damage Threshold of MgO-Doped LiNbO_3 Crystals

作　　者：苏卓琳 孟庆龙[1] 于军立 张彬[1] 

机构地区：[1]四川大学电子信息学院,四川成都610065

出　　处：《光学学报》2015年第11期226-233,共8页Acta Optica Sinica

基　　金：中国工程物理研究院太赫兹科学技术基金项目(CAEPTHZ201305);四川省教育厅创新团队计划(13Td0048)

摘　　要：在经典的双温模型中引入电子激发、载流子吸收等电离过程,建立了飞秒激光和晶体材料相互作用的理论模型。采用有限差分法数值模拟了在飞秒激光作用下,不同掺杂摩尔分数的Mg O∶Li Nb O3晶体内电子、晶格温度随飞秒激光脉宽、激光能量密度的变化规律。并定量分析了不同掺杂摩尔分数的Mg O∶Li Nb O3晶体材料的损伤阈值随脉宽的变化规律,以及掺杂浓度对晶体损伤阈值的影响。结果表明,在Li Nb O3晶体中掺入适量的Mg O将使载流子迁移率发生变化,进而会影响晶体的损伤阈值。在适当掺杂范围内,掺Mg O的摩尔分数越高,载流子迁移率越大,晶体的损伤阈值越高。因此,实际应用中可通过在Li Nb O3晶体中掺入适量的Mg O来提高晶体的抗损伤能力。The theoretical model of the interaction between femtosecond lasers and crystal materials is established, in which the effects of electron excitation, carrier absorption and other ionizing process are coupled into the classical double-temperature model. The variations of the electron and lattice temperature with the pulse duration and fluence of femtosecond lasers in MgO ： LiNbO3 crystals with different doping concentration are numerically simulated by the finite-difference method. Furthermore, the variation of damage threshold with the femtosecond pulse width and influence in different doping concentration MgO ： LiNbO3 crystals, as well as the influence of doping concentration on damage threshold are analyzed quantitatively. Results show that, in appropriate doping range, with relatively higher MgO-doped concentration, the carrier mobility of MgO ： LiNbO3 crystals increases, and the damage threshold of the crystals becomes higher. Consequently, the resist damage capability of LiNbO3 crystal may be raised by appropriate MgO doping in practical applications.

关 键 词：掺氧化镁铌酸锂晶体 飞秒激光 损伤阈值 双温模型 

分 类 号：O437[机械工程—光学工程]