Deyra Loïc, Martial Igor, Didierjean Julien, Balembois François, Georges Patrick
Opt Lett. 2014 Apr 15;39(8):2236-9. doi: 10.1364/OL.39.002236.
We demonstrate a deep-UV laser at 236.5 nm based on extracavity fourth-harmonic generation of a Q-switched Nd:YAG single-crystal fiber laser at 946 nm. We first compare two nonlinear crystals available for second-harmonic generation: LBO and BiBO. The best results at 473 nm are obtained with a BiBO crystal, with an average output power of 3.4 W at 20 kHz, corresponding to a second-harmonic generation efficiency of 38%. This blue laser is frequency-converted to 236.5 nm in a BBO crystal with an overall fourth-harmonic generation yield of 6.5%, corresponding to an average output power of 600 mW at 20 kHz. This represents an order of magnitude increase in average power and energy compared to previously reported pulsed lasers at 236.5 nm. This work opens the possibility of LIDAR detection of dangerous compounds for military or civilian applications.
我们展示了一种基于调Q Nd:YAG单晶光纤激光器在946nm处的腔外四倍频产生的236.5nm深紫外激光器。我们首先比较了两种可用于二次谐波产生的非线性晶体：LBO和BiBO。使用BiBO晶体在473nm处获得了最佳结果，在20kHz时平均输出功率为3.4W，对应二次谐波产生效率为38%。该蓝色激光在BBO晶体中被频率转换为236.5nm，总四倍频产生效率为6.5%，对应在20kHz时平均输出功率为600mW。与之前报道的236.5nm脉冲激光器相比，这代表了平均功率和能量提高了一个数量级。这项工作开启了用于军事或民用应用的危险化合物激光雷达检测的可能性。
