Ultra-efficient terahertz metamaterial sensor

Abstract

Subwavelength confinement of electromagnetic fields in metamaterials and plasmonic resonant structures makes them promising clinical diagnostic tool for biomolecular sensing. In this paper, we propose a novel negative refractive index meta-structure, in terahertz (THz) spectral range, which shows ultrahigh spectral response to the biological and chemical molecules (proteins, PTFE, etc.). We numerically investigate how meta-surface enables ultrahigh sensitivity, ultrahigh quality factor (QF), and high figure of merit (FOM) specificity for biomolecules (cancer cells, etc.). Two very sharp Fano type resonant dips (extremely narrow linewidth) in transmission spectra are obtained at f1=6.42THz and f2=7.73THz. A very high sensitivity level 1.34THz/Refractive Index Unit (RIU) for 1st resonant frequency and 2.5THz/RIU for 2nd resonant frequency is achieved. We develop an analytical model, which is in extremely good agreement with simulation results. We investigate the sensitivity of our sensor to sense the level of infection of the cancer cells. The obtained sensitivity of biosensor for cancer cells is quite high. Our simulation and analytical results show that the proposed device is extremely sensitive at both the resonance frequencies for thin and thick analytes (thickness range 5 µm–60 µm). Our findings would facilitate to design a real time biomolecular and chemical sensor in THz spectral range.