科研之友
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摘要
We propose an electrically tunable absorber based on epsilonnear- zero (ENZ) effect of graphene embedded in a nanocavity, which is composed of metal grating and substrate. Due to strong surface-normal electric field confined in ENZ graphene in the proposed structure, greatly enhanced light absorption (similar to 80%) is achieved in an ultrathin graphene monolayer. By electrically controlling the Fermi-level of graphene, a sharp peak absorption wavelength is tuned over a wide range. The proposed device can work as an optical modulator or a tunable absorption filter, which has a unique feature of incident angle insensitiveness owing to the ENZ effect and magnetic dipole resonance. Moreover, existence of a significantly dominant electric field and its uniformity make the device performance independent of the position of the graphene layer in the nanocavity, which provides great fabrication tolerance.
- 出版日期2015-12-28
