Dispersion of the quadratic susceptibility of barium-strontium niobate crystals and their structure

The dispersion of the quadratic susceptibility of barium-strontium niobate crystals was determined for the first time in the visible and near-ultraviolet parts of the spectrum. The results obtained were analyzed using an oscillator model allowing for the crystal structure of the niobate and for the dependence of the effective nonlinear polarizability of the Nb–O bonds on their length.