Patent ID: 6516012
Filing Date: 2003-02-04
Classification: H01S

Abstract:
An excimer or molecular fluorine laser, comprising:a discharge chamber filled with a gas mixture; a plurality of electrodes within the discharge chamber connected to a power supply circuit for energizing the gas mixture; and a resonator including said discharge chamber and first and second resonator reflecting optical elements for generating an output laser beam, wherein the first resonator reflecting optical element is an output coupling interferometer including a pair of opposing reflecting surfaces tuned to produce a reflectivity maximum at a selected wavelength for narrowing a linewidth of the output laser beam, and further comprising a first photodetector and a beam splitter, wherein said beam splitter is positioned to reflect a portion of the beam reflected from the output coupling interferometer to said photodetector, and further comprising a control unit which monitors a signal received at the first photodetector that varies according to a spectral tuning status of the interferometer, and wherein the control unit controls the spectral tuning status of the interferometer and thereby controls the signal received at the first photodetector so that the reflectivity maximum at the selected wavelength is controlled at least in part according to a known correspondence with the monitored signal received at the first photodetector, and wherein said interferometer is tuned substantially to a maximum intensity of interference fringes reflecting therefrom.