title: Efficient multiline nanosecond pulse amplification in planar waveguide CO₂ amplifier for extreme UV laser-produced plasma source.
abstract: In this Letter, we report on recent experimental results of a short pulse amplification at 10.6 μm wavelength required to drive a tin laser-produced plasma (LPP) extreme ultraviolet (UV) source. We report for the first time, to our best knowledge, a highly efficient pulsed amplification in a multipass amplifier built on RF-discharge-excited, diffusion-cooled CO2, planar waveguide industrial CO2 laser. About 2 kW of output average power was obtained from about 100 W input average power in ∼15  ns pulses at 100 kHz pulse repetition frequency. As much as 60% relative extraction efficiency, as compared to continuous-wave amplification in similar conditions, and 5.8% wall-plug efficiency was recorded and believed to be the highest reported so far. An improvement of extraction efficiency by ∼10% is reported when driving the amplifier with two lines of CO2 regular band in good agreement with expectations.
authors.forename: Krzysztof M
authors.initials: KM
authors.lastname: Nowak
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ohta
authors.forename: Takashi
authors.initials: T
authors.lastname: Suganuma
authors.forename: Junichi
authors.initials: J
authors.lastname: Fujimoto
authors.forename: Hakaru
authors.initials: H
authors.lastname: Mizoguchi
authors.forename: Akira
authors.initials: A
authors.lastname: Sumitani
authors.forename: Akira
authors.initials: A
authors.lastname: Endo