Narrow-band absorption enhancement and modulation of single layer graphene by surface plasmon polaritons in near-infrared region

Abstract

We theoretically study the very sharp absorption enhancement of the single layer graphene by the surface plasmon polaritons in near-infrared region. We place the single layer graphene on the silver substrate surface with a periodic slit array. Such a structure design is helpful to reduce the difficulty in experimental fabrication. By changing the slit period, we can largely tune the absorption peak of the single layer graphene in the wavelength range from 1000 nm to 2000 nm, covering the well-known communication wavelength of 1550 nm. The absorption efficiency of the single layer graphene varies between about 20 % and 80 %, and the absorption bandwidth is reduced from about 10 nm to 1 nm. Moreover, by changing the Fermi energy of the single layer graphene, we can also completely modulate the absorption peak from a maximum to almost zero and thus realize a nearly 100 % modulation depth. This work has a potential application in electro-optic modulators.