Picosecond CO/sub 2/ laser-pulse generation and amplification

The generation of 30-ps 10- mu m laser pulses from an optical-free-induction-decay (OFID) 10- mu m CO/sub 2/ laser system and the first realization of a UV-preionized high-pressure CO/sub 2/-laser-pulse amplifier with Ernst-electrode profiles for these ultrashort CO/sub 2/ laser pulses are described. For a given transverse electric discharge width, the Ernst profile makes it possible to position the UV-radiation sources nearer to the discharge than with the Rogowski or Chang profile. A more homogeneous preionization of the discharge area is possible. Thus, the amplifier works up to 15 bar with a laser-gas mixture of 5:5:90 (CO/sub 2/:N/sub 2/:He). The authors amplified 30-ps OFID 10- mu m CO/sub 2/-laser pulses up to ten times by passing through the amplifier twice. Thus, 10- mu m OFID pulse energies of 1 mJ were achieved. With the amplifier used as an oscillator, a maximum output energy of 600 mJ was obtained in longitudinal-multimode operation for 50-ns pulses.<
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