Optical vortices in antiguides.
We address the question of whether an optical vortex can be trapped in a dielectric structure with a core of a lower refractive index than the cladding--namely an antiguide. Extensive numerical simulations seem to indicate that this inverse trapping of a vortex is not possible, at least in straightforward implementations. Yet, the interaction of a vortex beam with a curved antiguide produces interesting effects, namely a small but finite displacement of the optical energy center-of-mass and the creation of a symmetrical vortex-antivortex pair on the exterior of the antiguide.
Dipartimento di Fisica, Università di Napoli Federico II, Napoli, Italy. marrucci@na.infn.it
Lorenzo
L
Marrucci
Noel F
NF
Smyth
Gaetano
G
Assanto