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 (F₄/Bg₅/F₄) and (Bg₅/F₄/Bg₅) where F₄ 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 YaBO₂CuO₇ 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 (F₄/Bg₅/F₄) is more sensitive to low temperature compared to (Bg₅/F₄/Bg₅). 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.