Numerical Simulations of Metamaterial Absorbers Employing Vanadium Dioxide

In this paper, we investigate various sensor configurations via optical metamaterial nano-absorbers. These are designed by two disparate triangle shapes nanoparticles. By using the three-dimensional (3D) finite difference time domain (FDTD) method, we numerically examine the absorption and the reflection spectra, sensitivity, and figure of merit (FOM). The effective medium theory (EMT) is applied to investigate the simulation results. Based on the simulation consequences, the two-aligned triangles model has maximum sensitivity and FOM. In the proposed sensors, maximum sensitivity becomes 283 nm per refractive index (RI), whereas its FOM is 3.8 × 103 RI−1. By studying the absorption performance, the incident angle (0°–60°) insensitivity is confirmed. Also, to provide tunability, we investigate the sensor by vanadium dioxide (VO2) thin film. We have demonstrated an absorber comprising a thin film of VO2 that can be tuned the absorption bandwidth by varying the temperature. Because of the spectral features of the designed devices, one can use them to identify biological samples like human blood type and ethanol and water concentrations of some matters.