81-PERCENT CONVERSION EFFICIENCY IN FREQUENCY-STABLE CONTINUOUS-WAVE PARAMETRIC OSCILLATION

We have studied doubly resonant parametric oscillation in the regime of maximum conversion efficiency. A monolithic MgO:LiNbO3 resonator with a threshold of 28 mW, pumped by a frequency-doubled Nd:YAG laser, was employed. With an active frequency-stabilization scheme, single-mode operation without mode hops at 105 mW combined signal and idler output power was achieved at a pump power four times above threshold, with a conversion efficiency of 81%. Excellent agreement between theory and experiment was found for the dependence of efficiency and depletion on pump power. The efficiency and the nearly complete pump depletion of 94% were limited only by imperfect mode matching of the pump wave and by the small cavity losses. (C) 1995 Optical Society of America