Methodology for optical studies of nonlinear crystals: application to the isomorph family , , and

We develop a methodology for the measurement of quadratic nonlinear optical properties of crystals. Our methods are mainly based on the use of the spherical geometry which allows, with only one crystal, accurate measurements of the phase-matching directions and the associated angular acceptances, double-refraction angles and effective coefficients. These data constitute a reliable basis for the modelling of the second-order electric susceptibility of crystals and for the comparison between materials.