由内腔倍频直接获取高功率皮秒准单脉冲

Generation of a Powerful QuasiSingle Picosecond PulseDirectly by Intracavity Frequency Doubling

描述采用ＢＢＯ（β－ＢａＢ２Ｏ４）非线性晶体，在被动锁模共焦非稳腔Ｎｄ∶ＹＡＰ脉冲激光器中实现高效腔内倍频，倍频能量转换效率为８０％．不需任何激光放大器和单脉冲选择器，首次在全被动锁模激光器中直接产生０．５４μｍ的高功率皮秒准单脉冲．准单脉冲能量大于２０ｍＪ，脉宽为十几个皮秒．同时，腔内倍频技术稳定了二次谐波输出，最大能量起伏由基波的１２．４％下降到倍频光的８．３％．

By adopting βBaB2O4 (BBO) crystal, a high performance intracavity frequency doubling is realized in passively modelocked confocal unstable cavity Nd∶YAP pulsed laser, with energy conversion efficiency of 80%. Needing not laser amplifier and single pulse selector, a powerful quasisingle picosecond pulse is directly generated at 0.54 μm in totally passively modelocked laser for the first time. The quasisingle pulse is imbued with energy more than 20 mJ and a pulsewidth of dozen of picoseconds. Besides, the technique of intracavity frequency doubling stabilizes second harmonic output; and causes the maximumenergy fluctuation to decrease from 12.4% in fundamental wave to 8.4% in frequency doubling light.