Tunable multichannel THz perfect absorption using graphene-based Fabry Perot resonator

The ability to enhance and manipulate light absorption is critical in many applications of optoelectronic devices. In order to achieve this purpose in the THz region, we design a THz absorber made up of graphene-based Fabry Perot resonator. We demonstrate that the proposed structure achieves multichannel perfect absorption because of Fabry Perot resonance leading to strong localization of light field. The absorber is polarization-insensitive and exhibits tolerance in a wide range of incident angles for both TE and TM waves. The number of absorption bands can be controlled by appropriately setting the thickness of the dielectric spacer between the graphene and the metal reflector. Moreover, the absorber is stable to the magnetic field, left-handed circularly polarized light, right-handed circularly polarized light and environment refractive index. This work may promote the development and applications in optoelectronic devices such as sensors, photodetectors and absorbers.