Compact Nd:YAG and Nd:YVO4 amplifiers end-pumped by a high-brightness stacked array

We analyze both theoretically and experimentally the performances of compact laser amplifiers longitudinally pumped by a high-brightness stacked array. Results are given for Nd:YAG and Nd:YVO4 as the active media. A model of amplification which takes into account the particular pumping configuration is presented to fit the experimental results. With less than 5-mm-long crystals, single-pass small-signal gain-length products of similar to 1.6 on a 1.5 mm x 1.5 mm aperture are demonstrated with optical-to-optical extraction efficiency of similar to 25%. The influences of the amplified spontaneous emission, crystal orientations, pump beam characteristics, and standing wave grating on the gain are also analyzed.