Efficient Vortex Generation in Subwavelength Epsilon-Near-Zero Slabs.
Phys Rev Lett
; 118(10): 104301, 2017 Mar 10.
Article
em En
| MEDLINE
| ID: mdl-28339254
ABSTRACT
We show that a homogeneous and isotropic slab, illuminated by a circularly polarized beam with no topological charge, produces vortices of order 2 in the opposite circularly polarized components of the reflected and transmitted fields, as a consequence of the transverse magnetic and transverse electric asymmetric response of the rotationally invariant system. In addition, in the epsilon-near-zero regime, we find that vortex generation is remarkably efficient in subwavelength 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 portions 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- or nanofabrication processes and can operate even at very small (ultraviolet) wavelengths.
Texto completo:
1
Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article