Goos–Hänchen and Imbert–Federov shifts of vortex beams near critical incidence

Abstract

We investigate the Goos–Hänchen and Imbert–Federov shifts of linearly polarized vortex beams undergoing internal reflection in a glass prism in the critical region of incidence. Beam shifts are numerically calculated based on a wavenumber-space representation. The influences of the beam’s topological charge, angle of incidence, and propagation distance on the beam shifts are investigated. We find that in the critical region, the Goos–Hänchen and Imbert–Federov shifts are coupled by the vortex beam’s orbital angular momentum. While the Goos–Hänchen increases with propagation distance, the Imbert–Federov shift is invariant with propagation. We show that both shifts exhibit a dependence on the beam’s topological charge beyond a simple linear proportionality.