Optical parameter oscillation with detuned intracavity sum-frequency generation

The authors consider frequency up-conversion by means of an optical parametric oscillator (OPO), in which sum-frequency generation (SFG) takes place in a crystal preceding the OPO crystal in the resonator. The SFG crystal produces light with a frequency at the sum of the pump and OPO signal frequencies. Only the OPO signal is resonated. A small detuning (phase mismatch) of the SFG crystal yields stable steady-state operation with quantum efficiency greater than 40% for a factor of 34 variation in the pump intensity. Detuning also reduces the power loading on the OPO crystal. As an example, conversion of 1.064 mu m radiation to 589 nm radiation is discussed. For this example, power conversion efficiency exceeding 85% is possible.<
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