Research on ultrashort-wavelength vacuum ultraviolet generation by using stimulated Raman scattering

我们提高了CsLiB6O10 （CLBO）的激光损伤容限，并尝试构建190 nm以下的真空紫外（VUV）激光源，作为反斯托克斯（as）激发拉曼散射（SRS）的新泵浦源。利用Nd:YAG激光器，经过多次变频，在1697.9 nm处产生了五次谐波和红外（IR） OPO。在最后阶段，利用CLBO中的五次谐波和红外共频产生190 nm以下的VUV光。从213 nm输入产生189 nm输出，转换效率为7.3%。在实验的基础上，利用20 w的峰值功率密度高的Nd:YAG激光器，设计了185nm的紫外激光系统。虽然我们目前正在构建系统的最后阶段，但我们估计平均功率超过100 mW，为185 nm，并且预计SRS在H2（如第1、3和8 as线）的超短波VUV辐射为172、150和115 nm。

We have improved laser-induced damage tolerance of CsLiB6O10 (CLBO), and attempted to construct vacuum-ultraviolet (VUV) laser source below 190 nm as a new pump source of anti-Stokes (AS) stimulated Raman scattering (SRS). By using an Nd:YAG laser, the fifth harmonic and infrared (IR) OPO at 1697.9 nm were generated via several frequency conversion stages. At the final stage, VUV light below 190 nm was generated by sum-frequency generation with the fifth-harmonic and IR in a CLBO. A 189 nm output was produced with a conversion efficiency of 7.3% from the 213 nm input. Based on the experimental result, we have newly designed VUV laser system at 185 nm using a 20-W Nd:YAG laser with high-peak power density. Although we are currently constructing the final stage in the system, we estimate the average power over 100 mW at 185 nm and expect ultrashort-wavelength VUV radiation by SRS in H2 such as 1st, 3rd, and 8th AS lines at 172, 150, and 115 nm.