Measurements of second-order nonlinear optical coefficients from the spectral brightness of parametric fluorescence

We report a new technique for determining second-order nonlinear optical coefficients that uses the spectral brightness of spontaneous parametric fluorescence. Measurements with this technique on two separate AgGaS2 crystals yielded values of 22.9 and 24.3 pm/V for |d36|, and measurements on a KTP crystal yielded 4.1 pm/V for |d24|. The uncertainty of the determined values is approximately ±10%.