VERY HIGH REPETITION RATE NARROW BAND GAS DISCHARGE LASER SYSTEM

PROBLEM TO BE SOLVED: To provide a gas discharge laser used for supplying narrow band light for integrated circuit lithography application.SOLUTION: A method and apparatus for producing a very high repetition rate gas discharge laser system in a MOPA configuration is disclosed which may comprise: a master oscillator gas discharge laser system producing a beam of oscillator laser output light pulses at a very high pulse repetition rate; and at least two power amplification gas discharge laser systems receiving laser output light pulses from the master oscillator gas discharge laser system, each of the at least two power amplification gas discharge layer systems amplifying some of the received laser output light pulses at a pulse repetition that is a fraction of the very high pulse repetition rate equal to one over the number of the at least two power amplification gas discharge laser systems to form an amplified output laser light pulse beam at the very high pulse repetition rate, which may be positioned in series with respect to the oscillator laser output light pulse beam.