Patent ID: 8687661

Claim:
A method of operating a gas-discharge laser for providing laser output in the form of laser output pulses, the laser including spaced-apart gas-discharge electrodes powered by a radio frequency power supply (RFPS), with a laser-resonator formed between the discharge electrodes, the method comprising: delivering a first train of RF sub-pulses from the RFPS to the gas-discharge electrodes for energizing the laser-resonator, each sub-pulse in the train including a plurality of cycles of RF energy, the RF sub-pulses in the first train of RF sub-pulses being temporally spaced apart by a time sufficiently short that the laser-resonator responds to the first train of RF sub-pulses as though the first train of RF sub-pulses were a single RF pulse, whereby the laser-resonator delivers a first laser-output pulse in response to the energizing by the first train of RF sub-pulses and: following delivery of the first train of RF sub-pulses, delivering a second train of RF sub-pulses from the RFPS to the gas-discharge electrodes for energizing the laser-resonator, each sub-pulse in the second train including a plurality of cycles of RF energy, the RF sub-pulses in the second train of RF pulses being temporally spaced apart by a time sufficiently short that the laser-resonator responds to the second train of RF sub-pulses as though the second train of RF sub-pulses were a single RF pulse, whereby, following delivery of the first single laser output pulse, the laser-resonator delivers a second laser-output pulse in response to the energizing by the second train of RF sub-pulses, and wherein one of the duration and number of RF sub-pulses in the second train thereof is selected such that the first and second laser output pulses have about equal power.