Investigation of a nonlinear multicomponent medium of a laser with controlled external feedback

A method for investigating the photorefractive effect in electro-optical crystals by intracavity spectroscopy, proposed earlier by the authors, is generalised to several other nonlinear optical effects. An analysis is made of the feasibility of measuring the characteristics of nonlinear optical media in which several quantum transitions with different lifetimes can take place. The effectiveness of the method is demonstrated by an investigation of a DKDP crystal at room temperature.