Enhanced Temperature Sensing Based on the Randomness in the Multilayered 1D Photonic Crystals

Abstract

A high sensitive temperature sensor is proposed based on the random properties of the one dimensional photonic crystal (1DPC). The structure is designed with two layers consisting of silicon (Si) and silica (SiO2) materials. The transmission spectra of the photonic crystals are studied at different temperatures from 25°C to 100°C. Thermal characteristics of the proposed random structures are examined with the effect of thermal expansion and thermo-optic effect. As the temperature increases the transmission peak shifts towards the longer wavelength due to the thermal parameters of the dielectrics used. It is found that the temperature-sensitive transmission peak shift is significantly improved due to the insertion of the third material that constitutes the ternary photonic structure (Si/SiO2/TiO2)N. For the above multilayer structures, based on the dependence of the layer thickness and the number of materials used, the numerical results show a sensitivity of 0.052nm/°C. When the third dielectric material (TiO2) is replaced by the polymer material (PS), the wavelength of the transmittance peak shift can be enhanced to 0.087nm/°C. These properties are useful for the fabrication of handy temperature sensors.