高重频掺钕钒酸钇激光器双程放大理论研究

为了提高高重频掺钕钒酸钇激光器的放大效率，提出了一种针对Nd:YVO₄单轴晶体的新型双程放大方式，采用法拉第隔离器与Nd:YVO₄晶体旋转45°放置的方式，使得种子激光在往返通过晶体时的线偏方向均为π偏振方向。结果表明，在100W抽运功率下，1W种子激光采用该双程放大方式的输出功率能够达到36.2W，放大效果较之偏振片与λ/4波片组成的双程放大结构提高了41.5%。本研究对以Nd:YVO₄单轴晶体为放大级的弱种子激光放大有重要意义。

Study on double-pass amplification of Nd:YVO4 laser system with high repetition

In order to improve the amplification efficiency of high repetition frequency Nd:YVO₄ laser, a new method of double-pass amplification for the uniaxial crystal like Nd:YVO₄ was introduced. The Faraday isolator and Nd:YVO₄ was placed with a rotation angle of 45°, and this method could be applied to keep the polarization direction of the seed laser in parallel with the Nd:YVO₄ c-axis. The simulation results show that the seed laser with 1W average power could be amplified to 36.2W in this double-pass amplification, and the amplification factor was improved 41.5% corresponding to a amplification method consisted with a polarizer and a quarter wave plate. This study is very important for laser amplify of weak seeds with Nd:YVO₄ as laser amplification.