Complex image processing in nonlinear crystals

摘要

Abstract: The optical properties and nonlinear response of photorefractive crystals of quartz and barium sodium niobate (BSN) are investigated in the temperature range of 20 - 700$DGR@C. The specl-structure of the laser beam in quartz crystal was observed in the narrow range of temperature at $alpha@-$beta phase transition. The elastic light scattering intensity of the quartz sharp increases at phase transition and drops after. The specl-structure in BSN crystal appears in the wide range of the temperature, from room temperature to the temperature of ferroelectric phase transition, Tc $EQ 560$DGR@C. The elastic light scattering in the BSN crystal rapidly decreases at the temperature Curie. The change of intensity of the elastic light scattering corresponds to the visually observed change in the laser beam trace in the crystals. The anomalies of scattering light probably reflect the structural changes associated with the formation of incommensurate phase in these crystals.!7