Transverse-flow radio-frequency-excited amplifier seeded by a cavity-dumped CO 2 laser for an extreme ultraviolet light source

A transverse-flow radio-frequency-exited CO2 laser amplifier was evaluated by a short-pulse seed laser. We constructed a prototype transverse-flow amplifier for the extreme UV laser-produced-plasma source. The electrical power for the discharge was enhanced to 100 kW at a 100% duty cycle. A Q-switched cavity-dumped CO2 seed laser emitting 13 ns pulses with a repetition rate of 100 kHz was amplified along a fivefold optical path in the amplifier gain medium. As a result, the amplifier output an average power of 3.07 kW with an 8.5 W laser input. The electrical-to-optical efficiency was 3.1%, which was far higher than that of axial-flow amplifiers at the same laser input power. The pulse showed a slight stretch from an input duration of 13 ns to an output of 15 ns.