Temperature Sensor Based on Deformed One-Dimensional Nanometallic Photonic Crystals

The theoretical investigation of the temperature dependence in hybrid one-dimensional photonic crystals with a metal defect involved simultaneously considering thermal expansion effect and thermal-optical effect. Firstly, we study the effect of the number of iterations in the H(LH)^NH(LH)^N and H(LH)^NSH(LH)^N systems, where H (GaAs) and L (Bi₄Ge₃O₁₂ “BGO”) are two different materials with constant refractive index nH (n_GaAs = 3.3) and nL (n_BGO = 2.31), respectively. S is a metal chosen as the Ag. The presence of metal S enhances noticeably the sensitivity for the temperature. It has been shown that when N increases the transmission peak λ_peak shifts to higher wavelengths for the structure H(LH)^NH(LH)^N. We show that the proposed device H(LH)^NSH(LH)^N can be used as a temperature sensor. Indeed, the sensitivity changes from the value 4.5 pm K^–1 in the absence of the metal layer to the value 17 pm K^–1 in its presence. Enhancing the sensitivity of the H (LH)^NSH(LH)^N component, we proceeded to a deformation of the system by the application of a law of the type y = x^1 + k, where y denotes the deformation coordinate of the structure H(LH)^NSH(LH)^N and x the coordinate before deformation. The degree of deformation is defined by the coefficient k. The value of N is chosen equal to 4. This value corresponds to the minimum of layers of the system leading to its satisfactory performance. We show in this case that the sensitivity increases by increasing the positive value of k.