Patent ID: 6735236
Filing Date: 2004-05-11
Classification: G03F,H01S

Abstract:
A grating based line narrowing device for line narrowing a laser producing high energy laser beams, said device comprising:(A) a grating defining a grating face, (B) a chamber for housing at least said grating, (C) a purge means for providing a purge gas for purging said chamber, (D) a beam expanding means for expanding a beam from said laser to produce an expanded beam, (E) a tuning means for directing said expanded beam onto the grating face in order to select from said expanded beam a desired range of wavelengths, wherein said expanded beam heats said grating face producing a temperature increase in said grating face which in turn heats purge gas in a purge gas layer adjacent to said grating face, and (F) a heat removal means comprising a purge gas flow of less than 20 liters per minute across said grating face remove heat from said purge gas layer to reduce optical distortion caused by said purge gas layer.