Patent ID: 6426966
Filing Date: 2002-07-30
Classification: H01S

Abstract:
A F2-laser, comprising:a discharge chamber filled with a gas mixture including molecular fluorine for generating a spectral emission including a plurality of closely spaced lines in a wavelength range between 157 nm and 158 nm including a primary line and a secondary line; a plurality of electrodes coupled with a power supply circuit for producing a pulsed discharge to energize said molecular fluorine; and a resonator including the discharge chamber, a transmissive etalon, and a pair of resonator reflectors for generating a laser beam having a bandwidth of around 1 pm or less, said etalon being configured for having a response maximum around the primary line for maximum transmissivity of said primary line and having a response minimum around the secondary line for relatively low transmissivity of said secondary line to substantially suppress said secondary line, thereby selecting said primary line such that said F2-laser emits a single wavelength laser beam having a narrow spectral linewidth that is less than the bandwidth of a free-running F2-laser to provide a narrow band VUV laser beam.