Narrow band gas discharge laser with gas additive

摘要: The present invention provides a very narrow band pulse excimer laser capable of producing pulses at rate in the range about 500 to 2000 Hz with enhanced energy dose control and repoducibility. Very small quantities stabilizing additive consisting oxygen or heavy noble gas (xenon radon for KrF lasers, krypton, xenon ArF lasers), are added mixture. Tests performed show substantial improvements stability addition 30 ppm laser. improved performance Lasers 6-10 Xe 40 Kr. In preferred embodiment, bandwidth is achieved on by reducing fluorine partial pressure less than 0.10 percent increasing reflectance output coupler greater 25 percent. prior art fused silica beam expansion prisms used line narrowing module were replaced calcium fluoride (see fig - specification devoid reference numeros).