Tunable perfect dual-narrowband absorber based on graphene-photonic crystal heterostructure

A dual-narrowband absorber in the terahertz (THz) band is proposed and numerically analyzed, which consists of a sheet of graphene on a photonic crystal (PC) heterostructure. We find a huge enhancement of absorption because optical Tamm states (OTSs) are excited at the interfaces of graphene-PC and PC heterostructure. The full width at half maximum (FWHM) of the absorption peak near the wavelength of 300 mu m can be as narrow as 1.25 mu m, and narrower FWHM can be obtained by adapting the wavelength and incident angle of the light beam. The wavelengths of absorption peaks and the absorptivities can be tuned by controlling the Fermi energy of graphene and the periods of PCs. In addition, the absorber can maintain high absorptivity over a wide incident angle range for both TE and TM polarization. The proposed optical absorber has potential applications in THz biosensors, filters, and switches.

Automated summary

A dual-narrowband absorber consisting of graphene and a photonic crystal heterostructure is proposed and analyzed in the terahertz band. The absorption is greatly enhanced due to the excitation of optical Tamm states at the interfaces. The absorber exhibits narrow full width at half maximum (FWHM) absorption peaks that can be tuned by controlling the graphene Fermi energy and photonic crystal periods, and it also maintains high absorption over a wide incident angle range for both TE and TM polarization. The proposed absorber has potential applications in THz biosensors, filters, and switches.