Theory of nonlinear hot-image formation in high-power lasers

A theoretical approach, based on the paraxial wave equation and the Fresnel integral, are presented to investigate nonlinear hot-image formation of an intense laser beam. Fresnel-zone-plate-like hologram induced by the sum of a wave scattered from a small scatterer and a background wave produces the negative first order diffracted wave (conjugative wave) that is focused to an traditional hot-image, and the negative second order diffracted wave that develops to an intense second-order hot-image. It is seen by the analytical results that the two images may attain a high intensity level enough to damage optical components in high-power lasers, showing that these two images should be equally taken into account for large lasers optimization of system design.