The effect of elliptical focusing on the threshold of a nanosecond BBO crystal optical parametric oscillator
The effect of elliptical focusing on the threshold of a nanosecond BBO crystal optical parametric oscillator
复制标题
椭圆聚焦对纳秒BBO晶体光参量振荡器阈值的影响
DOI：
10.1080/09500340.2019.1696996
复制
发表时间：
2019
影响因子：
1.3
通讯作者：
A. Ray
中科院分区：
文献类型：
--
作者：
C. S. Rao;G. Kondayya;S. Kundu;A. Ray
**摘要**：在本文中，我们报告了为确定高重复频率输入紫外（355nm）泵浦光束的最佳椭圆聚焦参数而开发的数值模型的结果，该参数用于实现基于单谐振纳秒β - BaB₂O₄（BBO）的光学参量振荡器（OPO）的可靠低阈值运行。分析预测，通过在椭圆焦点处优化355nm泵浦光束，有可能大幅降低OPO的阈值。我们利用模型计算找出了椭圆焦点的最大尺寸，在此尺寸下，基于I型BBO晶体的OPO的阈值脉冲能量可降低至约0.7mJ。这为基于纳秒BBO的多千赫兹重复频率的OPO提供了机会，该OPO由脉冲能量约为2 - 3mJ的二极管泵浦固体激光（DPSSL）系统的三次谐波泵浦，同时保持高平均功率。
ABSTRACT In this paper, we report the results of our numerical model developed to determine the optimum elliptical focusing parameters of the high repetition rate input UV (355 nm) pump beam for achieving reliable low threshold operation of a singly resonant nanosecond β-BaB2O4 (BBO) based optical parametric oscillator (OPO). The analysis predicts that it is possible to achieve a substantial reduction in the threshold of the OPO by optimizing the 355 nm pump beam in an elliptical focus. We have used our model calculations to find out the maximum size of the elliptical focus for which the threshold pulse energy of the Type-I BBO crystal based OPO is lowered to ∼0.7 mJ. This provides the opportunity for a multi-kHz repetition rate, nanosecond BBO based OPO, pumped with the third harmonic of a DPSSL system operating with a pulse energy of ∼2–3 mJ, while maintaining high average power.