Focusing of electromagnetic waves through a dielectric interface by lenses of finite Fresnel number

The problem of vectorial diffraction of electromagnetic waves is addressed. An integral representation is obtained for a possibly high-aperture, finite-Fresnel-number lens and a homogeneous medium of propagation. The solution is given in terms of coherent superposition of plane electromagnetic waves with position coordinates scaled with the well-known Li–Wolf scaling factor [J. Opt. Soc. Am. A 1, 801 (1984)]. This integral representation is then used to obtain formulas for the case in which light is focused through a plane dielectric interface. The solution is given by the linear combination of three functions, each of which consists of only a single integral. The aberration function, representing spherical aberration, is shown to be analytical. Numerical examples are given to demonstrate the effectiveness of the solution.