RAMAN-SHIFTED KRF LASER-RADIATION WITH LOW AMPLIFIED SPONTANEOUS EMISSION FOR A ROTATIONAL RAMAN DAYTIME-TEMPERATURE LIDAR

Various configurations of a tunable two-stage KrF laser have been inve stigated for providing powerful laser pulses with very low amplified s pontaneous emission (ASE). The lowest fraction (0.00017%) of ASE was a ttained with a single-pass amplifier and a phase-conjugate Brillouin m irror. The most suitable application envisaged for the laser source, i .e., remote daytime-temperature measurement by means of rotational Ram an scattering, is a dedicated oscillator-amplifier configuration with an ASE of 0.005% at an output of 300 mJ. The very low values of ASE we re measured with the aid of a thallium atomic-vapor filter.