Symmetry enhanced non-reciprocal polarization rotation in a terahertz metal-graphene metasurface.
Opt Express
; 26(3): 3328-3340, 2018 Feb 05.
Article
in En
| MEDLINE
| ID: mdl-29401862
ABSTRACT
In the present article we numerically investigated the magneto-optical behaviour of a sub-wavelength structure composed by a monolayer graphene and a metallic metasurface of optical resonators. Using this hybrid graphene-metal structure, a large increase of the non-reciprocal polarization rotation of graphene can be achieved over a broad range of terahertz frequencies. We demonstrate that the symmetry of the resonator geometry plays a key role for the performance of the system in particular, increasing the symmetry of the resonator the non-reciprocal properties can be progressively enhanced. Moreover, the possibility to exploit the metallic metasurface as a voltage gate to vary the graphene Fermi energy allows the system working point to be tuned to the desired frequency range. Another peculiar result is the achievement of a structure able to operate both in transmission and reflection with almost the same performance, but in a different frequency range of operation. The described system is hence a sub-wavelength, tunable, multifunctional, effective non-reciprocal element in the terahertz region.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Opt Express
Journal subject:
OFTALMOLOGIA
Year:
2018
Document type:
Article