Design and performance of novel communication system using two-dimensional photonic crystals

Dielectric PBG materials have received broad attention due to their distinguished performance in high-density integrated optics and multi-functional devices like ultra-compact switches, optical intensity modulator, novel sensor topologies, microwave generation and laser acceleration. We have theoretically worked photonic band structure parameters of different geometries. The photonic band structure computations are applied utilizing the MIT photonic-bands package (MPB). Eigenmodes are calculated in Fourier domain. Model calculations are based on two-dimensional periodic crystal structure. The lattices consist of square rods and gaps between the rods filled with air. Moreover, we have evaluated the nature of guide modes in W1 defect waveguide. For this purpose, we used the MIT Electromagnetic Equations Propagation (MEEP) software package for numerical calculations. Our results will make a positive contribute to the literature. The results of the present study will make a positive contribution to the literature and can be used for the design of efficient optical devices. © 2015 Elsevier GmbH. All rights reserved

Photonic band structures of ZnX (X = S, Se, Te)

Dielectric photonic band gap materials have received broad attention due to their distinguished performance in optical devices, microwave generation and laser acceleration. We have theoretically studied photonic band structure parameters of ZnX (X = S, Se, Te). The photonic band structure calculations are performed using the MIT photonic-bands package (MPB) to calculate eigenmodes frequency domain of Maxwell's equations with periodic boundary conditions. Eigenmodes are calculated in Fourier domain. Model calculations are based on two-dimensional periodic crystal structure. The lattices consist of cylindrical rods and gaps between the rods filled with air. Single-site zinc blende lattices are considered. In order to get "gap maps" we have calculated the gaps as a function of radius of the rods. Moreover we have calculated the nature of guided modes in line defect waveguide. Our results are in good agreement with those in the literature

High pressure phase transition in super-cell LiBH 4 : An ab initio prediction

LiBH 4 which have attracted considerable attention from researchers due to the crystal structure characteristics is a metal hydride that can bind four hydrogen atoms. LiBH 4 which has high gravimetric and volumetric hydrogen density shows phase transitions at high pressures. In this regard, we created and analyzed LiBH 4 structure based on the first principles calculations, and then obtained the super-cell LiBH 4 structure. We achieved the phase transitions up to 20 GPa pressure with 2 GPa regular intervals for the super-cell LiBH 4 . We observed the Pnma to Pnma*, Pnma* to P2 1 /c, and P2 1 /c to C2/c phase transitions and calculated the volume contractions accompanying these phase transitions. According to the obtained volumetric values, one can conclude that LiBH 4 can minimize the volumetric requirements of the hydrogen storage for systems that can be used at high pressures. Thus, the hydrogen storage capacity of LiBH 4 may increase at particular phases. © 2019 The Physical Society of the Republic of China (Taiwan

Photonic crystal structures: Beam deflector and beam router

We investigate the optical characteristic, transverse magnetic (TM) and transverse electric (TE) band of twodimensional (2D) square lattice photonic crystal structure, which is composed of cylindrical air regions positioned at the corners of the square shaped dielectric rods. We obtain the wide photonic bandwidths between TM1-TM2 and TM3-TM4 bands. According to the results, we demonstrate the band gaps close to each other in the TM and TE frequencies for proposed structures. The resulting photonic gaps are formed to be about 8% at the higher frequencies of TE modes (TE4-TE5) and TM modes (TM7-TM8 and TM9-TM10). In addition, we examine isotropically generated structures for light guiding properties and observe that the light is directed in a particular route without using any deflection. We also investigate the self-collimation effect with the designed structure. The obtained results reveal the influences of the radius of cylindrical air holes and the angle between these air holes on absolute and partial photonic band gaps. Moreover, we observe the TM and TE band gaps that overlap. It is thought that the obtained band overlap will provide an easy way to produce the photonic crystals in practical applications like photonic insensitive waveguide. It is also believed that these results can provide the photonic crystal structures to work as a beam deflecting and beam router in integrated optical circuit applications. © 2018 Chinese Physical Society and IOP Publishing Ltd

Photonic crystal structures: Beam deflector and beam router

We investigate the optical characteristic, transverse magnetic (TM) and transverse electric (TE) band of twodimensional (2D) square lattice photonic crystal structure, which is composed of cylindrical air regions positioned at the corners of the square shaped dielectric rods. We obtain the wide photonic bandwidths between TM1-TM2 and TM3-TM4 bands. According to the results, we demonstrate the band gaps close to each other in the TM and TE frequencies for proposed structures. The resulting photonic gaps are formed to be about 8% at the higher frequencies of TE modes (TE4-TE5) and TM modes (TM7-TM8 and TM9-TM10). In addition, we examine isotropically generated structures for light guiding properties and observe that the light is directed in a particular route without using any deflection. We also investigate the self-collimation effect with the designed structure. The obtained results reveal the influences of the radius of cylindrical air holes and the angle between these air holes on absolute and partial photonic band gaps. Moreover, we observe the TM and TE band gaps that overlap. It is thought that the obtained band overlap will provide an easy way to produce the photonic crystals in practical applications like photonic insensitive waveguide. It is also believed that these results can provide the photonic crystal structures to work as a beam deflecting and beam router in integrated optical circuit applications. © 2018 Chinese Physical Society and IOP Publishing Ltd

Photonic characteristics and microcavity structure of ZnX (X =S, Se, Te)

The dielectric photonic band gap materials have received broad attention due to their distinguished performance in optical devices, microwave generation and laser acceleration. We have theoretically studied photonic band structure parameters and defected structures of ZnX (X = S, Se, Te). The cavity was formed by a periodic sequence of holes in a dielectric waveguide, with a defect formed by a larger spacing between one pair of holes. The band structures of TE modes were obtained and the frequency/transmission calculations for different geometric structures were implemented. Then, the quality factor of resonance frequency for ZnX structures were examined. High levels of the quality factor values for these structures were obtained. It is proved that these structures carry the characteristics of photonic crystals. © 2017, National Institute of Optoelectronics. All rights reserved

Photonic characteristics and microcavity structure of ZnX (X =S, Se, Te)

The dielectric photonic band gap materials have received broad attention due to their distinguished performance in optical devices, microwave generation and laser acceleration. We have theoretically studied photonic band structure parameters and defected structures of ZnX (X = S, Se, Te). The cavity was formed by a periodic sequence of holes in a dielectric waveguide, with a defect formed by a larger spacing between one pair of holes. The band structures of TE modes were obtained and the frequency/transmission calculations for different geometric structures were implemented. Then, the quality factor of resonance frequency for ZnX structures were examined. High levels of the quality factor values for these structures were obtained. It is proved that these structures carry the characteristics of photonic crystals. © 2017, National Institute of Optoelectronics. All rights reserved

Planar photonic crystals biosensor applications of TiO2

We examine quality factor and sensitivity change depending on the resonant wavelength changing re- fractive index of surrounding liquid for TiO2 photonic crystal slab structure. Photonic crystal slab structure is used widely for biological materials such as proteins, antigens, DNA, cells, virus particles and bacteria. Mentioned photonic crystal slabs are usable with large-area biosensor designs. They permit direct access to externally incident optical beams in a microfluidic device. Model calculations are based on two-dimensional periodic crystal structure. Photonic crystal slab consists of a square lattice of air holes in a finite-thickness dielec- tric slab. The time domain simulations were implemented by software MIT Electromagnetic Equation Propagation

Photonic crystal bend and applications

In this study, 2D square lattice photonic crystal bend structure based on high index rods placed in air is designed by removing two cross lines of rods to realize two optical channels. The alteration of transmitted energy in the channels depending on rods radius changes is observed in the simulations. Time domain simulation results obtained by FDTD analyses exhibit that, when transverse magnetic (TM) Gaussian point source is applied from left channel, up to 92% of the incident energy can be channelized into a vertical channel. Variation of rods radius in the corner of bend affects considerable to the magnitude of reflected wave in the source channel and the time delay between the incident and reflected waves. Sensitivity analysis of W1 waveguide bend in a photonic crystal (PhC) is achieved to optimize PhC bend structure frequency response. Results of these numerical optimizations can be used to design novel compact switches and optical sensors. © 2012 Elsevier GmbH. All rights reserved

Planar Photonic Crystals Biosensor Applications of TiO2TiO_2

We examine quality factor and sensitivity change depending on the resonant wavelength changing refractive index of surrounding liquid for $TiO_2$ photonic crystal slab structure. Photonic crystal slab structure is used widely for biological materials such as proteins, antigens, DNA, cells, virus particles and bacteria. Mentioned photonic crystal slabs are usable with large-area biosensor designs. They permit direct access to externally incident optical beams in a microfluidic device. Model calculations are based on two-dimensional periodic crystal structure. Photonic crystal slab consists of a square lattice of air holes in a finite-thickness dielectric slab. The time domain simulations were implemented by software MIT Electromagnetic Equation Propagation