1064nm皮秒脉冲激发的外腔式SrWO_4拉曼激光器

External Resonator SrWO_4 Raman Laser Excited by 1064 nm Pico-Second Pulses

研究了SrWO_4晶体在外置谐振腔条件下对于皮秒激发脉冲的受激拉曼散射特性。采用提拉法生长了高光学质量的SrWO_4晶体,尺寸为φ22 mm×40 mm,质量为72.3 g。利用分光光度计测量了SrWO_4晶体的室温透过光谱,其透过短波限为260 nm,长波限大于3200 nm,因此可在较宽波长范围内实现拉曼激光频移。当激发源为脉宽40 ps的Nd:YAG锁模激光时,多波长拉曼输出的总转换效率达到73%,最大输出能量2.58 mJ;1180 nm一级斯托克斯拉曼输出的最高转换效率为38%,最大输出能量1.04 mJ;1324 nm二级斯托克斯拉曼输出的最高转换效率为19.3%,最大输出能量0.39 mJ。实验表明,SrWO_4晶体具有易生长、透光波段宽、增益系数大、转换效率高等优点,是一种有实际应用前景的固体拉曼介质。

External resonator stimulated Raman scattering of SrWO4 crystal excited by pico-second pulses is studied. SrWO4 crystal with high optical quality is prepared by Czochralski pulling method. Its size reaches Ф 22 mm× 40 mm, and its weight is 72. 3 g. The transmission spectrum of SrWO4 crystal is detected by spectrophotometer, which showes its short-wave limit is 260 nm, and long-wave limit is larger than 3200 nm. It indicates that SrWO4 crystal can realize Raman frequency shifting in a wide wave band. When the exciting source is a 40 ps Nd：YAG mode-locked laser, the total conversion efficiency for multi-wavelengths Raman output reaches 73%, and the largest output energy is 2.58 mJ. The highest conversion efficiency for the first Stocks Raman output of 1180 nm is 38%, and the largest output energy is 1.04 mJ. The conversion efficiency for the second Stocks Raman output of 1324 nm is 19.3 %, and the largest output energy is 0.39 mJ. The experimental results show that SrWO4 crystal possesses many advantages such as easy growth, wide transmittion spectrum, large gain coefficient, and high conversion efficiency, which indicate that SrWO4 is a promising solid Raman medium that may have practical applications.