High-sensitivity biosensor for identification of protein based on terahertz Fano resonance metasurfaces

Terahertz metasurface biosensors have gained significant attention in biological field due to its label-free, real-time and in-situ detection properties. In this paper, a planar array of Fano asymmetric split ring resonators (ASRs) fabricated on 25 mu m flexible polyimide substrate was proposed for new terahertz metasurface biosensors. It is shown that 160 GHz/RIU and 240 GHz/RIU refractive index sensitivity can be severally obtained near 0.81 and 1.13 THz transmission dips of the proposed system. Correspondingly, for biosensor samples that protein A/G, A/G + IgG were spotted on ASRs surface in our experiment, shifts of 8.9 GHz and 11.7 GHz, 17.6 GHz and 52.9 GHz toward low frequency were observed, respectively. These results illustrate high-sensitivity and label-free detection of proteins, implying a new feasible way of sensing in terahertz domain.