Optical recording of transient spatial structures in saturable three-level centres

Optical recording and decay of transient spatial structures is analysed in a system with a nonlinear response caused by incoherent saturation of three-level centres. The main attention is devoted to the thermal mechanism of phase recording in media with the temperature-independent heat conductivity. The relaxation of an inhomogeneous temperature field and the diffraction of a probe beam from the transient structure are studied.