Theory Design of a Virtual Polarizer with Multiscale and Multi-Biomass Sensing

Recently, more and more attention has been paid to human health with the rapid development of society. A designed virtual polarizer (VP) can realize multiscale and multi-biomass sensing, including temperature, cancerous cells, and COVID-19. Based on coherent perfect polarization conversion, a certain polarization conversion can be fulfilled within 1.72~2.14 THz. Then, through observing the displacement of a perfect matching point (PMP), variations in temperature can be accurately determined, covering from 299 K to 315 K, with a sensitivity (<i>S</i>) of 0.0198 THz/K. Moreover, a sharp coherent perfect absorption (CPA) peak generated from the VP can be employed for the detection of cancerous cells and COVID-19. The refractive index (RI) detection range of cancerous cells is from 1.36 RIU to 1.41 RIU with the sensitivity being -4.45881 THz/RIU. The average quality factor (<i>Q</i>), figure of merit (<i>FOM</i>), and detection limit (<i>DL</i>) are 825.36, 241.11 RIU^-1, and -36.83 dB. For the COVID-19 solution concentration (SC) from 0 mM to 525 mM, by mapping SC to RI, the RI sensing range is 1.344 RIU-1.355 RIU with the <i>S</i> being -5.03467 THz/RIU. The relevant <i>Q</i>, <i>FOM</i>, and <i>DL</i> are 760.85, 244.94 RIU^-1, and -36.89 dB. Based on two strategies of PMP and CPA, the proposed VP is capable of multiscale and multi-biomass sensing with excellent detection performance, providing a new detection method for biosensing.