PICOSECOND CO2 LASER-PULSE GENERATION AND AMPLIFICATION

This paper describes the generation of 30 ps 10 mum laser pulses from an optical-free-induction-decay (OFID) 10 mum CO2 laser system and the first realization of a UV-preionized high-pressure CO2 laser-pulse amplifier with Ernst-electrode profiles for these ultrashort CO2 laser pulses. For a given transverse electric discharge width, the Ernst profile permits 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 (CO2 : N2 : He). We amplified 30 ps OFID 10 muM CO2 laser pulses up to 10 times by passing the amplifier twice. Thus we reached 10 mum OFID pulse energies of 1 mJ. With the amplifier used as oscillator we have reached a maximum output energy of 600 mJ in longitudinal-multimode operation for 50 ns pulses.