Spatial Structure of Scattered Radiation in a Self-Pumped Photorefractive Passive Ring Mirror

We present detailed experimental investigation of scattered radiation spatial structure in the geometry of a transmission grating photorefractive passive ring mirror (Fig. 1) and compare our results with the predictions of Ref.[1]. According to the theory, behaviour of a ring mirror in the limit of large Fresnel numbers is determined by two scale variation coefficients: α// and α⊥. Scale variation coefficient α// is the ratio of the width of the pumping beam 4 in the plane of intersection to that of the pumping beam 2 (see Fig. 1). For | α// | <1 beam 4 is narrower and for | α// | >1 wider, than beam 2. The same with the scale variation coefficient α⊥, but for the direction, perpendicular to the intersection plane.