Analysis of influence of phase conjugate laser upon the threshold of optical parametric oscillator

The threshold of singly resonant KTP (θ=90°C,ψ=0°C) optical parametric oscillator was reduced significantly (about 50%) by use of stimulated brillouin scattering (SBS) phase-conjugate Nd:YAG laser as a pumping source comparing with the use of conventional multimode pumping source. Theoretical analysis shows that the OPO's threshold energy fluence depends on the pulse width, non-symmetrical temporal profile (sharp leading edge), and beam mode structure. The compressed pulse-width, sharp leading edge and single spatial mode with good beam quality contribute to the OPO's threshold reducing.