Narrow Results

In this work, we have introduced a comprehensive study concerning with the effects of some physical parameters on the dispersive properties of 1D phononic crystal (PnC). We have treated the propagation of elastic (in-plane) waves incident normally on 1D PnC. Based on the transfer matrix method, the reflection coefficients are calculated and plotted for the plane waves. We have studied many physical parameters effects on the properties of PnCs such as type of surrounding material, type of composites materials, temperature and propagation of waves in defect structures. Also the phenomenon of local resonance was discussed in this survey. These results can be useful in many applications such as sound suppressions and temperature sensor materials.

This paper reports the tunable transmission properties of asymmetric one-dimensional periodic structure (1DPS) composed of SiO₂ and anisotropic metamaterial (AMM) layers with defect of liquid crystal (LC) sandwiched by two SiO₂ layers, i.e., (SiO${}_2|$AMM)${}^3|$SiO${}_2|$LC$|$SiO${}_2|$(SiO${}_2|$AMM)³ using the transfer matrix method (TMM). We have studied the optical properties of the periodic structure (SiO${}_2|$AMM)³$|$SiO${}_2|$LC$|$SiO${}_2|$(SiO${}_2|$AMM)³ with a different incident angle of the electromagnetic wave for particular director angle of LC molecules. The tunability of the transmission property of the considered 1DPS shows that the transmittance depends upon the orientation of LC molecules. Such an asymmetric periodic structure (1DPS) composed of SiO₂ and AMM with a defect of LC sandwiched by two SiO₂ layers, (SiO₂$|$AMM)${}^3|$SiO${}_2|$LC$|$SiO${}_2|$(SiO${}_2|$AMM)³, may be used as a tunable optical filter and bi-stable device.

In this work, the transfer matrix method (TMM) is used to calculate the transmission of superconductor-dielectric 1D photonic crystal with central defect of semiconductor material (GaAs) at high superconductor critical temperature ($T_c)$. It is noticed that there is a red shift to high wavelength region by increasing the thickness of constituent materials. Also we study the effect of changing the incident angle, the doping density of GaAs and the applied pressure. The results show that the sense and change of photonic bandgap and transmittance peaks based on the thickness, incident angle, doping density of GaAs and hydrostatic pressure. In the case of change the thickness and hydrostatic pressure, the PBG and peak of transmittance shifted to higher wavelengths (red shift), while in the case of changing the incident angle and doping density, the PBG and peak of transmittance shifted to shorter wavelengths (blue shift).

In this study, we investigated the sensing capabilities of 1D defective photonic crystal designs composed of single and double defect layers. These structures can detect and distinguish minor refractive index changes of various organic samples infiltrated one by one into defect layer regions of the respective designs. We have used the standard transfer matrix method to analyze the transmission properties of both structures at normal incidence. The normal incidence has been chosen to overcome the experimental difficulties associated with oblique incidence. The performance of the proposed designs has been examined by measuring the shift in the position of the defect modes inside PBGs of respective structures depending upon the change in the refractive index of various organic solvents, called samples. We can also find adulteration in the organic samples by comparing the observed data with the experimentally available standard data of pure organic samples. Moreover, double defect photonic structure possesses pair of two defect modes inside PBG. These pair of defect modes are located on either side of bandgap edges that cannot be found in 1D defective PCs composed of a single defect. This intriguing property of double defect PC structure is due to the quasi Fabry–Perot cavity nature of the structure. Finally, we have compared sensing and detection features of both the designs made up of single and double defect photonic structures. It has been noticed that the double defect photonic structure also improves the transmittance of defect peak to unity compared to the single defect photonic structure. Moreover, the FWHM of two pairs of defect modes in double defect PC are opposite in nature. This remarkable feature of double defect photonic design may be very useful for improving the performance of photonic bio-sensors. It may be very helpful for designing some advanced bio-sensing designs whose defect mode properties are mirror image in nature.

Being able to manipulate light and confine it to small length scales have a multitude of applications in modern technology. Predicting the behavior of nanophotonic devices and the realization of new ones will greatly benefit from insights offered by analytical calculations and numerical modeling. In this paper, we elucidate the fundamental electromagnetic responses of materials and introduce a versatile technique, called transfer matrix method, in modeling the behavior of nanoscale heterostructures. Its application in novel photonic devices such as semiconductor microcavities and surface plasmon resonance sensors will be demonstrated.