Diode-pumped regenerative amplifier delivering 100-mJ single-mode laser pulses

We report on a side-pumped Nd:phosphate laser regenerative amplifier that d elivers laser pulses of as much as 100 mJ in a single TEM mode. The laser b eam is mode matched to the amplification medium by an intracavity fused-sil ica phase plate for mode shaping and a telescope for adjustment of the beam mode to the amplification rod section such that most of the energy stored in the rod is transferred to the laser pulses. As a result of the good over lap and the lour loss, an optical-to-optical conversion efficiency of as mu ch as 10% was measured for a pumping current of 80 A and greater than 100-m J output pulses. (C) 2001 Optical Society of America.