Nonlinear imaging properties under the coeffect of two wirelike opaque scatterers

Abstract

Nonlinear imaging in the propagation of a flat-topped circular Gaussian beam under the coeffect of two parallel wirelike opaque scatterers is investigated through computer simulation. The formation of hot images of each scatterer is proved. Moreover, the formations of two other kinds of intense images are found; one is called interference hot image and the other is called pseudo-second-order hot image. The former corresponds to one intense image fringe whose in-beam position is at the middle point between those of the two scatterers. This image fringe is in the plane a quarter of an object distance away from the exit surface of the Kerr medium slab, and its intensity is found comparable to that of the hot image. The latter corresponds to two intense image fringes in a plane near the second-order hot-image plane predicted for single phase-typed scatterer cases. The respective in-beam positions of these image fringes are close to the respective in-beam positions of the scatterers. Interestingly, the intensities of both kinds of images are found primarily determined by the copresence rather than the in-beam positions of the scatterers. Besides, though the hot-image intensity can be lower than the corresponding single opaque scatterer case, the maximum intensity inside the Kerr medium slab increases more quickly and thus is much higher at the exit surface. This is another threat to the safe running of the Kerr media for high-power laser systems.