高功率紫外超短激光脉冲光束质量研究

Beam Quality Research of High Power Ultraviolet Ultrashort Laser Pulse System

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。

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 qualityβ-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 andβ-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.