ABSOLUTE VALUE OF THE D(36) NONLINEAR COEFFICIENT OF AGGAS2 - PROSPECT FOR A LOW-THRESHOLD DOUBLY RESONANT OSCILLATOR-BASED 3 1-FREQUENCY-DIVIDER/

We report the measurement of the absolute d(36) nonlinear coefficient of silver gallium sulfide (AgGaS2) from three phase-matched nonlinear interactions spanning from 10.2 to 0.78 mu m: the sum-frequency of a C O2 laser (10.2 mu m) and a near-IR AlGaAs diode laser (0.842 mu m), th e second-harmonic generation of a KCl:Li color-center laser (2.53 mu m ), and the noncritically phase-matched 3 omega - omega --> 2 omega dif ference frequency between the AlGaAs diode laser and the KCI:Li laser to generate 1.265 mu m. From the theoretical evaluation of the Gaussia n-beam aperture functions for these type I interactions with arbitrary focusing parameters, beam-waist locations, and absorption losses, we have deduced from the three processes the same consistent value d(36) = 13 (+/- 2) pm/V for AgGaS2. Our value is independent of the growth o rigin of the material. In light of the trustworthy value of d(36) meas ured from our experiments we analyze the feasibility of a continuous-w ave doubly resonant parametric oscillator-(DRO-)based 3:1 frequency di vider pumped by a near-IR diode laser. The predicted pump power thresh old for the ring-resonator DRO lies in the range of 70-140 mW for a 14 -18mm-long sample with an absorption loss near the level of 1% cm(-1) at the output frequencies. (C) 1997 Optical Society of America.