Patent ID: 7903700
Filing Date: 2011-03-08
Classification: H01S

Abstract:
1. A narrow-spectrum laser device having an oscillation laser device that outputs a narrow-spectrum seed beam by causing a laser beam to pass through a wavelength dispersion element several times, and an amplification laser device or an amplifying device that amplifies the seed beam by discharging a laser gas within an amplification chamber, and outputs an amplified laser beam, the narrow-spectrum laser device comprising: spectral purity range measuring means for measuring a spectral purity range of a laser beam output from the amplification laser device or the amplifying device; and control means for controlling, while maintaining operations of the oscillation laser device, a measured spectral purity range of said laser beam output to be held within an allowable range of a target spectral purity range by retarding a discharge timing from a start of discharge by the oscillation laser device to a start of discharge by the amplification laser device or the amplifying device if the measured spectral purity range of said laser beam output is wider than the target spectral purity range, and by advancing the discharge timing if the measured spectral purity range of said laser beam output is narrower than the target spectral purity.