Tunable graphene lens

Graphene is known to exhibit a broad absorption peak at around 4.6 eV. This is attributed to resonant excitonic effects due to electron-hole interaction in the pi and pi star bands. Feeding on this extraordinary property of this single atomic layer, recent theoretical work has demonstrated that graphene layers can act as frequency tunable subwavelength imaging device in a proper configuration of a lens.

http://pubs.acs.org/doi/abs/10.1021/nn303845a