Polymeric Photonic Quasicrystal: Octonacci Sequence and Elasto-optic Effect

Here we would like to discuss the light transmission modulation by the one-dimensional polymeric quasi-multilayer which is formed according to substitutional generalized Octonacci with PMMA and PS as the constituent materials. In particular, we will present some theoretical findings using the well-known transfer matrix method. PBG inter-band spacing and depth can be managed by choosing the appropriate generation number. The number of PBGs is the same while increasing in the generation number and are shifted symmetrically towards the designed frequency. It also reveals the aroused forbidden frequency band can be manipulated by changing the applied hydrostatic pressure and the thickness of the constituent polymeric materials. The increase in pressure shows a blue shift in the PBGs while the increase in thickness of the polymeric material provides a redshift to PBGs. The proposed structure could be another possible system for optical device design specially multi-band tunable optical reflectors.

Realization of 3D reflectors by using metal-air and semiconductor-air based photonic structures at three communication windows

This study is based on analysis of 3D photonic crystal structure (PCS) for realization of photonic reflector pertaining to suitable optical communication wavelengths of 850, 1310 and 1550 nm. The said photonic reflector application is envisaged separately by two 3D PCSs, which comprise semiconductor (germanium) and metal (iron) based circular rods respectively, arranged on a square lattice having air as the background material. The plane wave expansion (PWE) technique is employed to investigate the photonic band gap (PBG) vis-à-vis all the aforementioned wavelengths. PBG is meticulously controlled by suitably selected various structure parameters, such as lattice spacing, diameter of the circular rods and nature of their material. Simulation outcomes explored that semiconductor based PCS reflects wavelengths of 850, 1310 and 1550 nm, when selecting the diameter of the circular rods as 282, 608 and 771 nm, respectively, whereas metal based PCS reflects the aforementioned wavelengths for diameters of the circular rods close to 335, 1070 and 871 nm, respectively. Further, we assayed the variation in reflected wavelength with respect to different diameters of circular rods for both proposed structures. Thus, the proposed optical reflectors can find a wide range of applications vis-à-vis three communication windows.

Engineering of Ultra-Violet Reflectors by varying Alternate Layers of Titania/Silica for Harmful UV-Protection

The primary requisite of engineering optical/photonic devices is either for scaling or altering the properties. Here, we present the engineering of ultra-violet (UV) reflectors made up of alternate layers of titania (TiO2) and silica (SiO2) by using the sol-gel spin coating method. The choice of these two materials is appropriate to realize the optical reflectors due to their large refractive index contrast. The formation of multilayer films of TiO2 and SiO2 are studied by field-emission scanning electron microscopy (FESEM), while UV-vis spectroscopy measurement is performed to study the reflectance. By varying the number of TiO2/SiO2 stacks, we have achieved the maximum reflectance within the UV region at center wavelength of 335 nm, 358 nm, and 367 nm corresponding to the 3, 6, and 9 stacks-based reflectors. Finally, we summarize that these reflectors prohibit the propagation of ultraviolet light, and therefore, they are promising as UV protection coating.

Design and modeling of optical reflectors for a PV panel adapted by MPPT control

Due to the highly non-linear electrical characteristics of photovoltaic generators (PVGs), the efficiency of PV systems can be improved by forcing the GPV to operate at their maximum power point (MPP). In this article, we are interested in concentrating Photovoltaic design to improve the output current of the panelwhile maintaining the DCDC boost element, after presenting the basic structure of Boost DC-DC converter, which shows the existence of a limitation on the voltage gain for this converter. In order to meet the specifications (high voltage gain and low ripple of the input current), existing structures will be presented that are able to provide a high voltage gain (Photovoltaic concentration) compared to another structure