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

We have redetermined the absolute values of the nonlinear optical coefficient, d(31), of LiNbO3 by parametric fluorescence and, for the first time, by difference frequency generation measurements to resolve the considerable discrepancy that existed between the values determined by second-harmonic generation (SHG) and parametric fluorescence. We obtain 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. It appears that the previous parametric fluorescence value, d(31)=5.8 pm/V, was overestimated.