graphene nanoribbon assisted refractometer based biosensor for mid-infrared label-free analysis

In this paper, an enhanced fabry-perot resonator (fpr)-based refractometer sensor is proposed using graphene nanoribbon (gnr) material to enable mid-infrared application. the fpr section consists of a three vertically aligned gnr sections: a conventional basic section placed in the middle complemented with two ending tail arms for auxiliary enhancement. to enable a real-world application of sensor, three-dimensional (3d) finite difference time domain (fdtd) simulations are performed. to apply dynamic gate bias tuning, the gnr layer is isolated from the substrate by means of a 50-nm layer of silicon dioxide (sio2), which is placed on top of a thick bulk silicon (si). to realize sensing application for the proposed enhanced fpr, a container is placed on fpr. refractive index sensitivity of the sensor is calculated to be in the range of 3180–4220 nm riu−1. to compare the superior performance of the sensor, a figure of merit (fom) is defined and extensively investigated. the fom of proposed sensor is found to be around 2.9–3.1 riu−1, which is a reasonable value compared to compact-sized on-chip-intended sensors. moreover, methods of dynamic variation of resonance wavelength are discussed, which can be useful for multi-analytic applications using spectral multiplexing of the sensor. the small footprint and its single- or multi-sensing application suggest that this enhanced fpr-assisted biosensor can be used as a lab-on-a-chip sensor for a label-free analysis.