高效全固化紫外四倍频激光器的研究

用半导体激光器抽运的调Q YLF倍频激光器抽运掺钛蓝宝石激光器，用LBO晶体在腔内产生二次谐波，再聚焦到BBO晶体上产生四次谐波深紫外激光。为了提高谐波转换效率，在腔内分别插入了单片、组合双折射滤光片和聚焦透镜，在平均功率为3.6W，波长为527nm的抽运光下得到410mW，417nm的蓝光。用长焦距的透镜聚焦二次谐波，得到34mW，208nm的紫外脉冲激光。从实验上详细研究了基频光的线宽对二次谐波效率的影响，二次谐波的线宽对四次谐波效率的影响、基频光的波长对四次谐波产生效率的影响。全面地分析了单片和组合大拆射滤光片及抽运功率对钛蓝宝石激光器基频光的脉宽、线宽等参量的影响。

Experimental Study of All-Solid-State Second Harmonic and Fourth Harmonic Generation in Ti∶Sapphire Laser

Second harmonic and fourth harmonic are generated by Ti: sapphire laser pumped by a diode laser pumped Q switched, frequency doubled YLF laser at 527 nm. The nonlinear crystal LBO is used to generate the second harmonic in the Ti: sapphire laser cavity at type I phase match with birefringent filter respectively, and BBO is used to generate ultraviolet laser at 208 nm. The maximum average power of 410 mW at 415 nm, and 34 mW at 208 nm are obtained at 1 kHz repetition rate when the pumping power is 3.6 W. The relations between linewidth of fundamental wave and harmonic efficiency, and wavelength of fundamental wave and fourth harmonic efficiency, the effects of birefringent filter on pulse width and line width of Ti: sapphire laser, and the dependence of line width of Ti: sapphire laser with birefringent filter on pumping power are investigated in theory and experiment.