Carbon Dioxide Gas Sensor Based on Polyhexamethylene Biguanide Polymer Deposited on Silicon Nano-Cylinders Metasurface

In this paper, we have numerically investigated a metasurface based perfect absorber design, established on the impedance matching phenomena. The paper comprises of two parts. In the first part, the device performance of the perfect absorber—which is composed of silicon nano-cylindrical meta-atoms, periodically arranged on a thin gold layer—is studied. The device design is unique and works for both x-oriented and y-oriented polarized light, in addition to being independent of the angle of incidence. In the second part of the paper, a CO(2) gas sensing application is explored by depositing a thin layer of functional host material—a polyhexamethylene biguanide polymer—on the metasurface. The refractive index of the host material decreases due to the absorption of the CO(2) gas. As a result, the resonance wavelength of the perfect absorber performs a prominent blueshift. With the help of the proposed sensor design, based on metasurface, the CO(2) gas concentration range of 0–524 ppm was detected. A maximum sensitivity of 17.3 pm/ppm was acquired for a gas concentration of 434 ppm. The study presented in this work explores the opportunity of utilizing the metasurface perfect absorber for gas sensing applications by employing functional host materials.