高功率紫外超短激光脉冲光束质量研究

通过搭建传输和聚焦光学系统,采用CCD相机测量了高功率紫外超短脉冲激光系统的光束质量参数,如紫外种子光及其经过KrF准分子激光器放大后的焦斑光强空间分布、焦斑尺寸及极限衍射倍数β。结果表明,紫外种子光光束质量良好,β接近于1。经放大后,光束质量劣化,β达到6左右。经分析,光学元件的表面缺陷可能是导致光束质量下降的主要因素。

Beam Quality Research of High Power Ultraviolet Ultrashort Laser Pulse System

By means of building transmitting and focusing optical system, the beam quality of high power ultraviolet ultrashort laser pulse system was researched by using a CCD camera. Relevant parameters obtained from the measurement are the spatial intensity distribution, the size of focal spot and beam quality β factor of the ultraviolet seed laser and the amplified pulse after its amplification by a KrF laser system. The result shows that the beam quality of the ultraviolet seed laser beam is good. β factor is closed to 1. After amplification the beam quality worsens and β factor increases to about 6. Through analysis, surface defects of optical elements may be the major factor which leads to the degradation of the laser beam quality.