Single-mode Nd : YAG laser with a self-pumped phase-conjugate loop cavity

A repetitively pulsed Nd:YAG laser with a self-pumped phase-conjugate loop cavity is proposed, A Sagnac interferometer is used as the end reflector, P arametric feedback is provided by a dynamic holographic gratings in the act ive elements and a passive LiF: F-2(-) laser Q-switch. It is shown that an additional amplifier and a half-wave plate inside the interferometer can in crease significantly the laser efficiency. An average radiation power of 12 0 W, a peak power of a single pulse of 6.9 MW, an experimentally achieved l aser efficiency of 2%, an angular divergence of 0.5 mrad, and a spatial bri ghtness of 10(14) W cm(-2) sr(-1) are reported.