%0 Journal Article
%T Wide Range Temperature Sensors Based on One-Dimensional Photonic Crystal with a Single Defect
%A Arun Kumar
%A Vipin Kumar
%A B. Suthar
%A A. Bhargava
%A Kh. S. Singh
%A S. P. Ojha
%J International Journal of Microwave Science and Technology
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/182793
%X Transmission characteristics of one-dimensional photonic crystal structure with a defect have been studied. Transfer matrix method has been employed to find the transmission spectra of the proposed structure. We consider a Si/air multilayer system and refractive index of Si layer has been taken as temperature dependent. As the refractive index of Si layer is a function of temperature of medium, so the central wavelength of the defect mode is a function of temperature. Variation in temperature causes the shifting of defect modes. It is found that the average change or shift in central wavelength of defect modes is 0.064£¿nm/K. This property can be exploited in the design of a temperature sensor. 1. Introduction Since the last two and half decades, investigations on various properties of photonic crystals, particularly photonic bandgap materials, have become an area of interest for many researchers [1¨C6]. It was observed that periodic modulation of the dielectric functions significantly modifies the spectral properties of the electromagnetic waves. The transmission and reflection spectra of such structures are characterized by the presence of allowed and forbidden photonic bands bands similar to the electronic band structure of periodic potentials. For this reason, such a new class of artificial optical material with periodic dielectric modulation is known as photonic bandgap (PBG) material [3]. Fundamental optical properties like band structure, reflectance, group velocity and the rate of spontaneous emission, and so forth can be controlled effectively by changing the spatial distribution of the dielectric function [4, 5]. This fact has opened up important possibilities for the design of novel optical and optoelectronic devices. Conventional photonic crystals have periodic modulation of homogeneous refractive indices, and they are artificially fabricated with periods that are comparable to the wavelength of the electromagnetic waves. These photonic crystals lead to formation of photonic bandgaps or stop bands, in which propagation of electromagnetic waves of certain wavelengths is prohibited. A one-dimensional photonic crystal (1D PC) structure has many interesting applications such as dielectric reflecting mirrors, optical switches, filters, and optical limiters. It has also been demonstrated theoretically and experimentally that 1D PCs can have absolute omnidirectional PBGs [7¨C11]. In addition to the existence of wide bandgaps in some properly designed PCs, the feature of a tunable PBG is an interesting property of such PCs. The PBG can be tuned by
%U http://www.hindawi.com/journals/ijmst/2012/182793/