Graphene Nano-Ribbon Assisted Fabry–Pérot Resonator Based Mid-Infrared Bandpass Filter

in this study, an ultra-compact optoelectronic band-pass filter is proposed. A single piece of graphene nano-ribbon (GNR) is placed in between of two input-output GNRs to form a Fabry-Perot-like cavity. The GNR - as mid-infrared surface waveguide – enhances the compatibility with complementary metal oxide-semiconductor processing technologies. By modulation of surface charge carrier density -simply changing the bias voltage applied on the GNR cavity- the transmission characteristics of band pass filter are tuned (Other than conventional means such as cavity material or scale modifications) and thus a room temperature tunable filter is achieved. It is found that increasing the gate voltage as well as increasing the silica substrate thickness, the max peak of filter’s transmission spectra alters toward smaller wavelengths (blue shift). In contrast, increasing the middle GNR length redshifts max peak of filter toward longer wavelengths.