Nonlinear imaging properties of two parallel gain-typed wirelike scatterers

Abstract

Based on the optical path model for nonlinear imaging, we systematically investigated the propagation of flat-topped Gaussian beam which is modulated by two parallel gain-typed wirelike scatterers through computer simulation. It is found that hot image for each scatterer can be formed, with the hot image plane several centimeters behind the predicted conjugated plane obtained by the approximate theory for attenuation-typed scatterers. It is found that the object distance, i.e. the distance from the scatterer plane to the incident surface of the Kerr medium slab, has an important influence on the propagation properties and results in a new phenomenon. Under certain object distances, the evolution of the maximum intensity of the beam has one prominent peak before that for hot image, where the on-axis location is dozens of centimeters ahead of the hot image plane. As the size of the scatterers increases, the value of this peak increases at first and then decreases. As the object distance increases, the value of this peak decreases. The intensity distribution corresponding to this peak shows that, there is an intense fringe, which is the most intense fringe in the plane, at the middle point of the line connecting the two scatterers, indicating that it is a unique result of the interaction of the two scatterers. Besides, the influences of the object distance and the scatterer size on hot image intensity are discussed.