Dual-Band Metasurface Cross-Polarization Converter For Cancer Detection In Terahertz Band

We present a metasurface based cross-polarization converter for label-free detection of cancerous cells in the terahertz band, through the principle of refractive index (R.I.) sensing. We measure the shift in frequency corresponding to maximum cross-polarization conversion when an analyte layer is placed on top of it. Owing to the difference between R.I. of healthy and cancerous cells and high sensitivity of metasurfaces to R.I. of surrounding media, we characterize the analyte sample as healthy or cancerous by measuring this shift. Moreover, two resonant frequencies of the proposed structure significantly reduces the measurement errors, thereby increasing accuracy. We report sensitivities equal to 155 GHz/RIU and 350 GHz/RIU at first and second resonant frequencies respectively. The proposed structure is simulated using finite element method and validated with an equivalent circuit model.