Aspherical behavior of the Kerr medium irradiated by laser Gaussian beam

The aspherical lens is an optical element used to effectively reduce optical aberration, a consequence of reducing the number of spherical surfaces in the complex optical system. In this paper, we suggest that a nonlinear lens formed in the Kerr medium irradiated by the laser Gaussian beam will be the aspherical lens. The expression describing the transverse distribution of index inside Kerr medium concerns the nonlinear coefficient of refractive index, and the laser intensity is derived approximately limited to the fourth-order term of the Maclaurins formula for Gaussian function. Based on the paraxial approximation, the expression of surface profile (sag) and the spherical aberration of the nonlinear aspherical lens are introduced and used for the numerical simulation of the model of the organic dye thin layer irradiated by laser Gaussian beam. The obtained results confirm the aspherical surface of the nonlinear aspherical lens and the spherical aberration has very low visible wavelength. The capability to reduce and neglect the spherical aberration when using the nonlinear lens as an aspherical surface in a complex optical system or a nonlinear lens for optical tweezers is discussed.