Patent ID: 7630424

Claim:
A method of operating a line narrowed pulsed excimer or molecular fluorine gas discharge laser system comprising: a seed laser oscillator producing an output comprising a laser output light beam of pulses comprising: a first gas discharge excimer or molecular fluorine laser chamber; and a line narrowing module within a first oscillator cavity; and a laser amplification stage containing an amplifying gain medium in a second gas discharge excimer or molecular fluorine laser chamber receiving the output of the seed laser oscillator and amplifying the output of the seed laser oscillator to form a laser system output comprising a laser output light beam of pulses, comprising: a ring power amplification stage; the method comprising: selecting a differential timing between an electrical discharge between a pair of electrodes in the first laser chamber and in the second laser chamber which at the same time keeps ASE below a selected limit and the pulse energy of the laser system output light beam of pulses essentially constant.