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 layer system producing a beam of oscillator laser output light pulses
at a very high pulse repetition rate; at least two power amplification gas discharge
laser systems receiving laser output light pulses from the master oscillator gas
discharge laser system and each of the at least two power amplification gas discharge
laser 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. The apparatus and method may further comprise a beam delivery
unit connected to the laser light output of the power amplification laser system.
The apparatus and method may be a very high repetition rate gas discharge laser
system in a MOPO configuration. The apparatus and method may comprise a compression
head comprising a compression head charge storage device being charged at x times
per second; a gas discharge chamber comprising at least two sets of paired gas
discharge electrodes; at least two magnetically saturable switches, respectively
connected between the compression head charge storage device and one of the at
least two sets of paired electrodes and comprising first and second opposite biasing
windings having a first biasing current for the first biasing winding and a second
biasing current for the second biasing winding and comprising a switching circuit
to switch the biasing current from the first biasing current to the second biasing
current such that only one of the at least two switches receives the first biasing
current at a repetition rate equal to x divided by the number of the at least two
sets of paired electrodes while the remainder of the at least two magnetically
saturable switches receives the second biasing current. The apparatus and method
may be utilized as a lithography tool or for producing laser produced plasma EUV light.