二阶非线性飞秒激光技术的研究

Research on Quadratic Nonlinear Technologies for Femtosecond Lasers

讨论了若干利用二阶非线性效应的飞秒激光技术研究进展。基于传统的钛宝石飞秒激光器,提出了可产生稳定的1μm波段可调谐飞秒激光的新型注入式飞秒光参量放大(OPA)系统。结合相位匹配折返原理,用部分氘化KDP晶体作为二阶非线性介质,实现了对20nm带宽的1μm波段飞秒激光的高效宽带倍频,倍频效率达到55％。最后介绍了具有脉冲扩展功能的时间望远镜系统。

The recent progress of the authors＇ group on developing quadratic nonlinear technologies for femtosecond lasers is reviewed. A novel injective femtosecond optical parametric amplifier （OPA） is developed, which can produce tunable femtosecond laser with central wavelength at 1μm, based on the traditional Ti：sapphine laser. A wideband frequency doubling efficiency, as high as 5596, for femtosecond pulsed laser with central wavelength at 1μm is realized, by using the phase matching reentry principle and adopting partially deuterated KDP crystal as the quadratic nonlinear medium. Finally, a time telescope of femtosecond laser with functions of pulse expanding and spectral narrowing is demonstrated.