THz Spectroscopy of Graphene Layers Using Guided-Mode Resonance Notch Filter

We measured sheet conductivity of graphene layers using an all-dielectric single-layer guided-mode resonance filter (GMRF) operating in the high-frequency terahertz (THz) region. The GMRF is a combination of a grating on the filter surface and slab waveguides of the filter substrate. Recently, high quality (Q) factor GMRFs have been developed at THz frequencies [1]–[3]. Because the Q-factor of GMR is very high, the resonance frequency and amplitude are very senstive to the properties of the material in contact with the GRMF. The resonant frequency and amplitude caused by GMRF are directly related to the conductivity of the material coated on the GMRF surface.