A Tunable Optimized Low-Temperature Sensor Based on the Hybrid Photonic Crystals (F4/Bg5/F4) and (Bg5/F4/Bg5)

In this paper, we present a novel type of low-temperature sensor based precisely on the symmetrical hybrid photonic crystals. Thanks to the two-fluid model and the transfer matrix method, we study the temperature sensitivity of the hybrid multilayers (F-4/Bg(5)/F-4) and (Bg(5)/F-4/Bg(5)) where F-4 represents the fourth iteration of the quasi-periodic Fibonacci sequence and Bg5 designates the multilayer Bragg mirror (HLS)(5). We assume that the layers H, L, and S indicate precisely the dielectric materials of Bi4Ge3O12, SiO2, and YaBO(2)CuO(7) superconductor one. The analysis of the transmittance spectra shows that the hybrid photonic crystal is more sensitive to the temperature than the periodic one. A higher sensibility value is reached due to the possible combination of the periodic and quasi-periodic sequences. Our investigation reveals that the photonic crystal (F-4/Bg(5)/F-4) is more sensitive to low temperature compared to (Bg(5)/F-4/Bg(5)). The sensitivity is significantly affected by the position of quasi-periodic sequences. The sensitivity of such photonic crystals can be adequately controlled by applying a symmetrical chirping. The designed structures pave the way toward the achievement of a potential low-temperature sensor.