Patent ID: 6173000
Filing Date: 2001-01-09
Classification: H01S

Abstract:
An excimer laser comprising:an oscillator having a first discharge tube filled with a gas having a lifetime of not more than 30 nanoseconds, said oscillator generating a laser beam having a cross-sectional shape as initially defined by said first discharge tube, said oscillator including means for selecting a bandwidth of said laser beam from a range of bandwidths defined by said gas and means for maintaining said cross-sectional shape of said laser beam within said oscillator and as said laser beam exits said oscillator;an amplifier receiving said laser beam exiting said oscillator, said amplifier including a portion of said first discharge tube and a second discharge tube filled with said gas to form a multi-pass amplifier, said amplifier causing said laser beam to pass once through said first discharge tube and then traverse multiple passes through said second discharge tube, wherein said laser beam is directed along a unique return path to said second discharge tube between successive ones of said multiple passes;first means disposed in a path of said laser beam defined between said oscillator and said second discharge tube for restricting laser beam divergence along said path; andsecond means disposed in each said unique return path for restricting laser beam divergence along each said unique return path, whereby divergence of said laser beam is decreased alone said path and each said unique return path while output energy, laser locking efficiency and tunability are increased resulting in an increased spectral brightness for said excimer laser.