In high power eximer laser system, amplified spontaneous emission (ASE) decreases the signal contrast ratio severely, leads to waveform broadening and distortion, and impacts on accurate physical experiments. In this article, based on principle of short pulse generation by electro-optical (E-O) switch, a method for ASE suppression of laser amplifiers chain was established. A series of studies on UV electro-optical switches were carried out, and electro-optical (E-O) switches with high extinction ratio were developed. In the waveform clipping experiments of the first pre-amplifier, the extinction ratio of the single and cascaded dual E-O switch reaches 10³ and 10⁴ order of magnitude, the laser pulse signal contrast ratio was promoted to 10⁵ and 10⁶ level, respectively. In the experiments of single channel MOPA (Master Oscillator Power Amplifier system), the cascaded dual E-O switch was adopted to suppress ASE of the whole system, and a fine narrow pulse was obtained on the target surface, which gives out one effective solution to the problem of waveform amplification of the high power eximer laser system.

Date Published: 16 May 2013
PDF: 10 pages
Proc. SPIE 8796, 2nd International Symposium on Laser Interaction with Matter (LIMIS 2012), 879624 (16 May 2013); doi: 10.1117/12.2011272

Published in SPIE Proceedings Vol. 8796:
2nd International Symposium on Laser Interaction with Matter (LIMIS 2012)
Stefan Kaierle; Jingru Liu; Jianlin Cao, Editor(s)