Effects of pump heating on laser and spectroscopic properties of the Nd:[YAl3(BO3)4] self-frequency-doubling laser

In this work, thermal effects on the spectroscopic and laser properties of Nd:YAl3(BO3)(4) crystal caused by pump heating are systematically investigated. Changes in the refractive indices, absorption coefficient, and emission band shape have been studied in a temperature range 20-200 degrees C. Temperatures up to 88 degrees C have been measured in a thermally isolated crystal when pumping with 800 mW of laser power at 807 nm. A decrease in infrared laser power at 1.06 mu m and its second harmonic (0.53 mu m) generated by self-frequency doubling is observed during the early seconds of laser operation. These reductions are explained in terms of the absorption efficiency reduction and of thermal phase mismatch (for second harmonic) induced by pump heating. Instabilities observed in the output (infrared and green) laser power during the initial seconds of laser action are satisfactorily explained in terms of Fabry-Perot-induced interference effects. (C) 2000 American Institute of Physics. [S0021-8979(00)03803-2].