Patent ID: 6477193
Filing Date: 2002-11-05
Classification: G03F,H01S,H03K

Abstract:
An extreme repetition rate gas discharge laser capable of operating at pulse repetition rates in the range of 4,000 to 6,000 pulses per second, said laser comprising:A) a laser chamber having two elongated electrodes, defining a discharge region and containing laser gas, B) a squirrel cage type tangential fan for circulating said laser gas producing sufficient gas velocities in said discharge region to clear from said discharge region, following each pulse, substantially all discharge produced ions prior to a next pulse when operating at a repetition rate in the range of 4,000 pulses per second or greater, C) a finned heat exchanger system capable of removing at least 16 kw of heat energy from said laser gas, D) a pulse power system configured to provide electrical pulses to said electrodes sufficient to produce laser pulses at rates of at least 4,000 pulses per second with precisely controlled pulse energies in the range of about 5 mJ to 10 mJ, and E) a laser beam measurement and control system capable of measuring pulse energy energy wavelength and bandwidth of substantially every pulse with feedback control of pulse energy and wavelength, and F) a liquid cooled motor, defining a rotor and a stator, driving said tangential fan, said motor comprising; 1) a pressure cup sealing member separating said stator from said rotor and protecting said stator from said laser gas and 2) a breach detection means for detecting a breach of said sealing member.