4-PASS AMPLIFIER FOR THE PULSED AMPLIFICATION OF A NARROW-BANDWIDTH CONTINUOUS-WAVE DYE-LASER

We demonstrate a new type of four-pass dye laser amplifier that can re duce the possibility of parasitic oscillation between optical componen ts used in the amplifier. Pumping the amplifier with a 5.6-mJ Q-switch ed doubled Nd:YAG laser output, we obtain high-peak-power pulsed outpu t of an incident cw narrow-bandwidth dye laser beam with a power gain greater than 2 x 10(6). Subsequent amplification of the pulse with a c onventional dye amplifier yields 42% energy efficiency. When a tempora lly stretched pumping pulse is used, the eventual bandwidth of the fin al output is measured to be 130 MHz. (C) 1996 Optical Society of Ameri ca