信号光脉冲比抽运光窄12倍的内腔式KTP光参量振荡器

在闪光灯抽运的非稳腔Nd∶YAG被动调Q激光器腔内,放置非临界相位匹配KTP晶体,构成内腔式单谐振KTP光参量振荡器(OPO)。研究了输出信号光的波长调谐性能,获得1.57~1.60μm可调谐激光脉冲。实验结果表明,1.57μm信号光的输出能量随着光参量振荡器腔长的增加而减少,脉冲宽度随着腔长的增加而有所变化;抽运能量较大时,转换效率随着抽运能量的增加趋于饱和然后逐渐下降;对此给予了合理的理论解释。当光参量振荡器的腔长为5 cm,1.06μm抽运光脉冲宽度为30 ns时,输出的1.57μm信号光的脉冲宽度为2.5 ns,能量为21.3 mJ。1.57μm信号光的脉冲宽度仅为1.06μm抽运光脉冲的1/12,总的电光能量转换效率为0.128%。

Intracavity KTP Optical Parametric Oscillator with Signal Pulse Shorter 12 Times than Pump Pulse

A single resonant intracavity KTP optical parametric oscillator (OPO) is constituted by placing a non-critical phase-matched KTP crystal in a flashlamp pumped and passive Q-switched Nd∶YAG laser with an unstable resonator. The wavelength tuning property of output signal laser is studied and the tunable laser pulses of 1.57～1.60 μm are obtained. The experimental results show that the output energy of signal laser at 1.57 μm decreases, and the pulse duration changes to some extent, with the increase of the cavity length of the optical parametric oscillator. When the pump energy is larger, the energy conversion efficiency goes to saturation with the increasing of pump energy, and then drops gradually. And a reasonable interpretation is given theoretically. When the cavity length is 5 cm and the pulse duration of pump laser at 1.06 μm is 30 ns, the pulse duration and output energy of signal laser at 1.57 μm are 2.5 ns and 21.3 mJ respectively. The pulse duration of signal laser at 1.57 μm is only 1/12 of that of the pump laser at 1.06 μm, and the electro-optical energy conversion efficiency is 0.128%.