Search query: Photonic Crystals PBG

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abstract: Abstract In this paper, the optical spectra of one dimensional photonic crystal (PCs) are numerically investigated in UV, Visible and Infrared ranges. PCs consisting of a HTc superconducting material (YaBa2Cu3O7) are sandwiched between dielectric layer (SiO2 or AlN) and semiconductor layer (GaAs) where superconducting layer is considered as defects. Using transfer matrix method, all the numerical results are performed and inferred that photonic band gap shifted to higher wavelengths by increasing the temperature. It is found that when the temperature increases the PBG shifted to a long wavelength. When the defect is used in structure as dielectric or superconductor, the peak appears in PBG and his value increases as the temperature increases.
author_names: Arafa H Aly

S E -S Abdel Ghany
title: Theoretical studies of hybrid multifunctional YaBa2Cu3O7 photonic crystals within visible and infra red regions
year: 2020

abstract: We present the structuring of different graded index materials in the form of one dimensional (1D) photonic crystals (PCs) for highly efficient light trapping and controlling photonic devices in terms of tuned and controlled photonic bandgap (PBG) performance. We consider hyperbolic, exponential, and linear refractive index variation in the graded index layer. We systematically study the influence of structural and grading parameters on the bandgap performance for two different graded photonic crystal (GPC) structures formed by stacking different graded index layers. Compared with conventional PCs, the GPC bandgaps can be changed and tuned by the refractive index profile of the graded index layer. We show that the number of bandgaps increases with the graded index layer thickness and the bandgap frequencies can be tuned by the grading profiles. We observe the sequential increment in bandwidth for the complete PBGs in the GPC structures with linear, exponential, and hyperbolic graded index materials. We also study the influence of the stacking pattern and grading profiles on the bandgap, phase shift, group velocity, delay time, and field distribution. The proposed GPC configurations facilitate the design of reflectors, multi channel filters, detectors, and other photonic devices. The study may also provide the basis of understanding of the influence of graded index materials on the PBG characteristics in the GPCs.
author_names: Bipin Kumar Singh

Ashish Bijalwan

Praveen C Pandey

Vipul Rastogi
title: Multi channel photonic bandgap consequences in one dimensional linear, exponential, and hyperbolic graded index photonic crystals
year: 2020

abstract: The slow photon effect can significantly increase the effective optical path length of light and thereby enhance the interaction of light with matter, which would be realized by light propagating at the edges of the photonic band gap (PBG) in photonic crystals (PCs) In this paper, a novel anodic oxidation method with effective voltage pulse compensation was developed to prepare one dimensional titania nanotube photonic crystals (1D TiO2 NT PCs) with a high quality of PBG, which could be continuously adjusted and precisely tailored just by modulating the anodization parameters. With the increase of low voltage (Lv) duration, the precise blue shift of the PBG of 1D TiO2 NT PCs was recorded. Through the precise tailoring of PBG in bandgap engineering, the edges of the PBG could be designed and purposely tuned to overlap with the electronic band gap range of the TiO2 material, and the as prepared 1D TiO2 NT PCs were used as a photocatalyst to degrade methyl orange (MO) molecules due to the enhanced slow photon effect and scattering effect in their highly ordered channel structures. Meanwhile, strategies to enhance the slow photon effect at the edge of the PBG were discussed and evaluated in detail according to our experimental and simulated results. This study would provide a new guide to taking advantage of the slow photon effect to enhance the photocatalytic activities, photoluminescence, and performances of other optoelectronic devices.
author_names: Xiao-Tian Wang

Xiao-Gang Wang

Cheng-wei Wang
title: Bandgap engineering of TiO2nanotube photonic crystals for enhancement of photocatalytic capability
year: 2020

abstract: Abstract In this paper, different types of binary gases were detected by the silica photonic crystals (PCs) It is found that the regulation of gas sensing is very different when silica PCs exposure to different types of binary gases. Here, silica PCs were prepared by the vertical deposition method. The performance of gas sensing was monitored by the shift of photonic band gap (PBG) of PCs. It is noteworthy that we convert the shift of PBG into the volume fraction of adsorption in order to investigate the adsorption behavior. For small molecule gases, the maximum of adsorption volume fraction of binary gases is smaller than two of the single gases. While for volatile organic compounds (VOCs) the maximum of adsorption volume fraction of binary gases locates between the two individual gases. The different types of gases follow different adsorption model, which are discussed in this work.
author_names: Hu Wang

Penghui Bai

Juan Xie

Lei Zhang

Kai Lei

Biao Liu

Chenjie Wang

Linghui Zhu

Guangyong Wang
title: Gas sensing of silica photonic crystals for binary gases
year: 2020

abstract: Abstract The Graphene patch antennas is widely used due to high electrical conductivity, high mobility, and saturation velocity in THz band. In a Terahertz (THz) band, high gain antennas to be preferred to minimized the atmospheric attenuation and path losses. In this article, the enhanced radiation characteristics graphene based antenna array design concept is proposed by using homogeneous substrate, photonic band gap crystal (PBG) substrate and superstrated dielectric grating. The projected graphene based 2x1 patch array antennas works as a resonance patch with complementary split split split ring resonator (CSSSRR) for the frequency range from 0.84 THz to 0.94 THz. The tunable property of graphene material and PBG substrate are investigated by varying the chemical potential m c of graphene sheet and different radius of hollow cylinders respectively. The minimum return loss of 57.052 dB, peak gain of 14.69 dB and directivity of 15.5 dBi are achieved with the planned antenna employing with superstrated dielectric grating structures. The suggested 2x1 graphene patch antenna array are operating in low atmospheric attenuation window henceforth suitable for the application of medical imaging, threat detection, and THz wireless communication.
author_names: Ritesh Kumar Kushwaha

P Karuppanan
title: Enhanced radiation characteristics of graphene based patch antenna array employing photonic crystals and dielectric grating for THz applications
year: 2020

abstract: Abstract Engineering of multi channel photonic band gap sensing consequences has been demonstrated in hyperbolic graded index materials embedded one dimensional (1 D) photonic crystal (PC) in the frequency 150 850 THz region. The multi channel photonic band gap sensing properties have been investigated by taking into account the reflection and photonic band gap (PBG) spectra of the proposed PC structures. For quarter wave stacking, we obtain single optical reflection band for band region 646.8 434.3 THz with the constituted normal layer refractive index 1.5. Band regions and bandwidths of the single PBG channel can be modulated by changing the refractive index of the constituted normal layer and grading parameter of the hyperbolic graded layer. The number of photonic bands increases with increasing the layer thickness of the GPC structures and leads to work as multi channel PBG sensors. The operation frequency of the multi channel PBG sensors can also be tuned by changing the constituted normal layer and grading parameter of the hyperbolic graded layer. These properties lead to design the tunable multi channel optical sensors/filters engineering. Moreover, the demonstration of the reflection phase shift, group velocity, group delay, and electric field distributions shows the effect of hyperbolic graded index materials on the propagation of light in 1 D PCs. With the engineering of tunable PBGs and structure controllability, hyperbolic graded index materials embedded 1 D PCs provide a promising way to fabricate tunable optical reflectors and multi channel optical sensors/filters for future optical devices.
author_names: Bipin Kumar Singh

Vaishali A Bambole

Vipul Rastogi

Praveen C Pandey
title: Multi channel photonic bandgap engineering in hyperbolic graded index materials embedded one dimensional photonic crystals
year: 2020

abstract: All inorganic cesium lead halide perovskite semiconductors exhibit great potential for nanolasers, light emitting diodes, and solar cells, because of their unique properties including low threshold, high quantum efficiency and low cost. However, the high material refractive index of perovskite semiconductors hinders light extraction efficiency for photonic and illumination applications. In this paper, we demonstrate high light extraction efficiency achieved in CsPbBr2.75I0.25 two dimensional photonic crystals. The perovskite photonic crystals exhibit both emission rate inhibition and light energy redistribution simultaneously. We observed a 7.9 fold reduction of spontaneous emission rate with a slower decay in CsPbBr2.75I0.25 photonic crystals, because of the photonic bandgap effect (PBG) We also observed a 23.5 fold PL emission enhancement, as a result of light energy redistribution from 2D guided modes to vertical direction in perovskite photonic crystals thin films, indicating a high intrinsic light e.
author_names: Songyan Hou

Aozhen Xie

Zhenwei Xie

Landobasa Y M Tobing

Jin Zhou

Liliana Tjahjana

Junhong Yu

Chathuranga Hettiarachchi

Cuong Dang

E H T Teo

Muhammad Danang Birowosuto

Hangzhou Wang
title: Concurrent Inhibition and Redistribution of Spontaneous Emission from All Inorganic Perovskite Photonic Crystals
venue: ACS Photonics
year: 2019

abstract: A new structure to control the electromagnetic waves has been successfully designed for smart windows applications. The present photonic crystals (PCs) smart window is designed from a unit cell of two different materials such as A (metal) and B (superconductor) of thicknesses that repeated for N periods. The numerical results are investigated based on the characteristic matrix method. It was found that the angle of incidence has a significant effect on the transmission values. At 10o angle of incidence, we found more than 80% of the visible light and a near IR is transmitted whereas at 60o angle of incidence, the photonic band gap (PBG) begins to appear at wavelengths greater than 800 nm and the visible light transmittance remains more than 80% Also, the dependence of the transmittance values on the periodicity and thickness of the proposed design was investigated. The proposed structure could be of potential use as a smart window in low temperature applications and space industry.
author_names: Arafa H Aly

Ayman A Ameen

Hussein A Elsayed

Sodky H Mohamed

Mahi R Singh
title: One Dimensional Metallo Superconductor Photonic Crystals as a Smart Window
year: 2019

abstract: Upconversion fluorescent material such as NaYF4:Yb/Re (Re is lanthanide ions) nanoparticles has considerable application prospect, but the fluorescence efficiency is usually too low. In this paper, an effective approach has been validated to enhance the fluorescence intensity of NaYF4:Yb/Re by coupling with SiO2 opal photonic crystals (PCs) NaYF4:Yb/Tm and NaYF4:Yb/Er were prepared by thermal decomposition method and ligand exchange, and then spin coated on the surface of SiO2 opal PCs with different photonic band gap (PBG) The PBG properties of PCs/UCNPs composite films were measured by transmission spectra. The effect of overlapping extent between PBG and UCNPs' emission on upconversion emission enhancement was studied through fluorescence spectra. The result shows that when the SiO2 opal PCs with the PBG at 448 nm were composited with NaYF4:Yb/Tm, the upconversion fluorescence at 450 nm was enhanced mostly, which is 34 fold. Similarly, the highest enhancement, 23 fold, was observed for fluorescence of NaYF4:Yb/Er at 541 nm when composited with SiO2 opal PCs having PBG at 544 nm. According to the analysis, the upconversion fluorescence can be enhanced through coupling with PCs by utilizing the light reflection and light localization effect of PCs. At the same time, the highest enhancement is obtained when the PBG of PCs is exactly overlapping with the wavelength of upconversion fluorescence. Our study potentially will contribute to promoting the sooner practical application of upconversion nanoparticles.
author_names: Yihao Shi

Fuqing Zhang

Jiao Xu

Kaihua Zhou

Chen Chen

Jian Cheng

Ping Li
title: Upconversion fluorescence enhancement of NaYF4:Yb/Re nanoparticles by coupling with SiO2 opal photonic crystals
venue: Journal of Materials Science
year: 2019

abstract: Abstract In this paper, we have theoretically investigated the optical spectra of all superconducting aperiodic photonic crystals comprising from different superconductors namely high high, low low and high low temperature configurations. Also, the name Octonacci is composed of Octo from octagonal and acci from the Fibonacci sequence, however, the Octonacci sequence has a geometric origin. In order to show the difference between TE and TM polarized lightwaves, we have analyzed both the influence of the incident angle and temperature of light wave on the PBGs as well as transmittance resonance peaks. By the way, the possibility of obtaining deep photonic band gap (PBG) has been provided for both TE and TM polarizations for the most incident angles. This study also investigates the effect of generation number of the Octonacci sequence on the PBG spectrum within the visible range. The results show that optical performances of Octonacci all superconducting aperiodic photonic crystals are higher than Fibonacci ones even with upper generations. Finally, to show the impact of the results, we have made a comparison between this new investigating quasi periodic sequence and periodic all superconducting ones.
author_names: Mehdi Zamani

Mansoureh Amanollahi

Abdesselam Hocini
title: Photonic band gap spectra in Octonacci all superconducting aperiodic photonic crystals
venue: Physica B: Condensed Matter
year: 2019