An optically pumped single mode laser, e.g. Nd:YAG crystal (20) with planoconcave mirrors is increased in efficiency by an order of magnitude to about 8% by optics (25, 27) for focusing the high power multimode output of laser diode arrays (21, 22) into the mode volume (20') of the laser medium (20)....http://www.google.de/patents/USRE34729?utm_source=gb-gplus-sharePatent USRE34729 - Method and apparatus for efficient operation of an optically pumped laser
