With the due course of properties of light, an optimum amount of the energy of the guided light is in form of evanescent waves which are very sensitive to changes occurring in the external environment, forms multilayer structural photonic band gap by propagating electromagnetic waves of certain wavelengths. The electromagnetic (EM) waves with frequencies falling within Photonic Band Gaps (PBGs) [1, 2] cannot propagate through the structure. The localized states can be created in the PBGs by introducing defects into the periodical structures. Due of their ability to control the propagation of light and the possibility of many new optical devices, PCs have been investigated intensively recently. If the PBG can reflect EM waves incident at any angle with any polarization, then an omnidirectional band gap (OBG) can be achieved with negligible loss within a specific frequency range [3-6]. It found out that one-dimensional PCs (1DPCs) may have OBGs, and the general conditions for obtaining OBGs in 1DPCs are presented in NUMERICAL METHOD and it has potential applications [7, 8], such as, omnidirectional terahertz mirrors , controllable switching , tunable polarizer , narrow- band filters , and refractometric optical sensing , etc.
One-dimensional ternary photonic crystals (1DTPCs) are also put forward to obtain the extended OBGs [11, 14-19]. 1DTPCs are constituted by three material layers in a period of the lattice. The wavelength range of OBGs can be enhanced by 108nm when the structure was modified by sandwiching a thin layer of ZrO2 between every two layers demonstrated by Awasthi et al . When the sandwiched layer was CeF3, the enhancement in the range was 120 nm. The OBGs can be significant enlarged in the ternary metal-dielectric PC shown by Wu et al. . The zero-reflective-phase bandgap will be enlarged by sandwiching the third material between the two single- negative materials proposed by Xiang et al. . An OBG in 1D ternary plasma PC is suggested by Kong et al. . Furthermore, some applications based on the 1DTPCs are also prospected, such as the tunable optical filter , and optical sensing device .
In this view highly sensitive sensors can be developed by using the property refraction of light with the calculation of refractive index. In addition, the important parameters, including sensitivity and detection limit, are also estimated. This estimation results that the refractometric sensor exhibits the capability of detecting an index variation of 10-6. The simulations are helpful for studying and developing new miniaturized optical sensors with high sensitivity.
In this present era, photonic band gap structures [1, 20] by virtue of refraction of light had drawn a lot of attention under various experiments [21-49], due to their enormous applications in optical communications, optoelectronics and optical instrumentation as well as in application in practical life. These photonic band...