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. (authors)