Generation of complex Gaussian beam modes in beam interaction with a planar dielectric interface

The problem of Gaussian beam interaction with a planar interface separating two semi-infinite homogeneous isotropic lossless media is considered for regular incidence, i.e., excluding the case of total internal reflection. The reflected and refracted fields are expressed in terms of the fundamental and higher order complex beam modes. These newly identified complex beam modes differ from the conventional beam modes and they describe the structure of the reflected and transmitted fields in a more convenient manner.