ABSOLUTE MEASUREMENT OF 2ND-ORDER NONLINEAR-OPTICAL COEFFICIENT OF LINBO3 BY PARAMETRIC PROCESSES

We have redetermined the absolute values of the nonlinear optical coef ficient, d(31), of LiNbO3 by parametric fluorescence and, for the firs t time, by difference frequency generation measurements to resolve the considerable discrepancy that existed between the values determined b y second-harmonic generation (SHG) and parametric fluorescence. We obt ain d(31)=4.8+/-0.5 and 4.3+/-0.5 pm/V at the pump wavelengths of 488 and 532 nm, respectively, in reasonable agreement with the SHG data. I t appears that the previous parametric fluorescence value, d(31)=5.8 p m/V, was overestimated.