A Graphene Based Metasurface with Wideband Absorption in the Lower Mid Infrared Region

An ultra-thin (~λ/34) graphene based metasurface exhibiting wide bandwidth in lower mid-infrared region has been discussed in this paper. The unit cell of the structure composes of graphene-based fractal geometry on the top surface depicted over amorphous silicon dioxide (SiO₂) whose bottom side is completely graphene deposited. The geometrical dimensions of the deposited graphene pattern are chosen so that broadband absorption is achieved between 1.75 THz and 7.28 THz with more than 90% absorptivity. Two distinct absorption peaks have also been observed at 3 THz and 7 THz in the aforementioned broad absorption spectra. The designed prototype has been observed under different incident angles of the incoming electromagnetic wave for both TE and TM polarizations where bandwidth improved absorption has been observed upto 60° incident angles for both cases. The structure is also found to be polarization independent in nature.