Efficient vortex generation in sub-wavelength epsilon-near-zero slabs

Abstract

We show that a homogeneous and isotropic slab, illuminated by a circularly polarized beam with no topological charge, produces vortices of order two in the opposite circularly polarized components of the reflected and transmitted fields, as a consequence of the difference between transverse magnetic and transverse electric dynamics. In the epsilon-near-zero regime, we find that vortex generation is remarkably efficient in sub-wavelength thick slabs up to the paraxial regime. This physically stems from the fact that a vacuum paraxial field can excite a nonparaxial field inside an epsilon-near-zero slab since it hosts slowly varying fields over physically large portion of the bulk. Our theoretical predictions indicate that epsilon-near-zero media hold great potential as nanophotonic elements for manipulating the angular momentum of the radiation, since they are available without resorting to complicated micro/nano fabrication processes and can operate even at very small (ultraviolet) wavelengths.

References in corpus (8)

• Spin-orbit interactions of light
• Optical spin-to-orbital angular momentum conversion in inhomogeneous anisotropic media
• Epsilon-Near-Zero (ENZ) Metamaterials and Electromagnetic Sources: Tailoring the Radiation Phase Pattern
• Spin-to-orbital angular momentum conversion in focusing, scattering, and imaging systems
• Geometric Metasurface Fork Gratings for Vortex Beam Generation and Manipulation
• Extreme nonlinear electrodynamics in metamaterials with very small linear dielectric permittivity
• Spin-to-Orbital Angular Momentum Conversion in Semiconductor Microcavities
• All-optical modulation in wavelength-sized epsilon-near-zero media

Cited by in corpus (6)

• Vectorial vortex generation and phase singularities upon Brewster reflection
• Spin-controlled photonics via temporal anisotropy
• Goos-Hänchen and Imbert-Fedorov Shifts for Epsilon-Near-Zero Materials
• Enhanced beam shifts mediated by Bound States in Continuum
• Generic Optical Singularities in Brewster-reflected Post-paraxial Beam-fields
• Observation of Larmor-like precession of a single birefringent particle due to spin-dependent forces in tilted optical tweezers