【摘要】 用半导体抽运的Q开关YLF倍频激光器抽运钛宝石晶体 ,在平凹腔内加入组合的石英双折射滤光片压缩线宽 ,用LBO晶体腔内激发二次谐波 ,聚焦到BBO上产生四次谐波深紫外光。在抽运功率 3 8W时 ,输出6 10mW ,4 16nm蓝光。用长焦距的透镜聚焦二次谐波 ,得到 6 4mW ,2 0 8nm的紫外激光。基频光的谱线宽度是决定倍频效率的关键因素。实验观察到激光器的频谱宽度与双折射滤光片的带宽有一个数量级的差别 ,考虑到模式竞争和增益饱和效应 ,数值模拟了加入双折射滤光片后的钛宝石激光器的实际线宽 ,结果与实验中测量的数据基本一致。实验还分析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激发效率的影响。更多还原

【Abstract】 Second harmonic and fourth harmonic are generated from Ti∶sapphire laser pumped by a diode-Q-switched, doubling-frequency YLiF 4 (YLF) laser at 527 nm. The nonlinear crystal LiB 3O 5 (LBO) is used to generate the second harmonic wave in the Ti∶sapphire cavity at Ⅰ-phase match with birefringent filter, and β-BaB 2O 4 (BBO) crystal is used to generate ultraviolet at 208 nm. Maximum average power of 610 mW at 416 nm, and 64 mW at 208 nm are obtained at 1 kHz repetition rate when the pumping power is 3.8 W. The high conversion efficiency is attributed to the birefringent filter which narrows the linewidth of Ti:sapphire laser. Considering mode-competition and gain saturation, the dependence of line width of Ti∶sapphire laser with birefringent filter (BF) on pumping power is investigated in theory and experiment, and there is good agreement between theoretical and experimental results.更多还原