Ayako KITAMOTO, Takashi KONDO, Ichiro SHOJI and Ryoichi ITO

Department of Applied Physics, Faculty of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113 Japan

(Received May 10, 1995; Accepted June 20, 1995)

We have redetermined the absolute values of the nonlinear optical coefficient, d₃₁, 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 d₃₁=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, d₃₁=5.8 pm/V, was overestimated.

Key words : absolute measurement, second-order nonlinear optical coefficient, parametric fluorescence, difference frequency generation