Photonic Band-Gaps in Porous Silicon Based Mirrors with a Ellipse Profile Refractive Index

2011 ◽  
Vol 236-238 ◽  
pp. 1811-1813
Author(s):  
Shuan Ming Li ◽  
Fu Ru Zhong ◽  
Zhen Hong Jia ◽  
Min Tian

We investigate the use of ellipse refractive index structure to enlarge photonic band-gap (PBG). The PBG structure was prepared on porous silicon with 10 unit cell. Each unit cell is consisting of 21 layers with the refractive index varying according to the envelope of the ellipse function. The width of this photonic band-gap is high to 451nm.

2019 ◽  
Vol 116 (47) ◽  
pp. 23480-23486 ◽  
Author(s):  
Michael A. Klatt ◽  
Paul J. Steinhardt ◽  
Salvatore Torquato

We show that it is possible to construct foam-based heterostructures with complete photonic band gaps. Three-dimensional foams are promising candidates for the self-organization of large photonic networks with combinations of physical characteristics that may be useful for applications. The largest band gap found is based on 3D Weaire–Phelan foam, a structure that was originally introduced as a solution to the Kelvin problem of finding the 3D tessellation composed of equal-volume cells that has the least surface area. The photonic band gap has a maximal size of 16.9% (at a volume fraction of 21.6% for a dielectric contrast ε=13) and a high degree of isotropy, properties that are advantageous in designing photonic waveguides and circuits. We also present results for 2 other foam-based heterostructures based on Kelvin and C15 foams that have somewhat smaller but still significant band gaps.


JETP Letters ◽  
1999 ◽  
Vol 69 (4) ◽  
pp. 300-305 ◽  
Author(s):  
L. A. Golovan’ ◽  
A. M. Zheltikov ◽  
P. K. Kashkarov ◽  
N. I. Koroteev ◽  
M. G. Lisachenko ◽  
...  

2019 ◽  
Vol 43 (41) ◽  
pp. 16264-16272 ◽  
Author(s):  
V. V. Vipin ◽  
Parvathy R. Chandran ◽  
Animesh M. Ramachandran ◽  
A. P. Mohamed ◽  
Saju Pillai

Enhanced fluorescence was achieved by tuning the photonic band gaps in colloidal photonic crystals and host–guest chemistry.


2003 ◽  
Vol 788 ◽  
Author(s):  
Martin Maldovan ◽  
Chaitanya K. Ullal ◽  
Craig W. Carter ◽  
Edwin L. Thomas

ABSTRACTA level set approach was used to study photonic band gaps for dielectric composites with symmetries of the eleven face centered cubic lattices. Candidate structures were modeled for each group by a 3D surface given by f(x,y,z)-t=0 obtained by equating f to an appropriate sum of structure factor terms. This approach allows us to easily map different structures and gives us an insight into the effects of symmetry, connectivity and genus on photonic band gaps. It is seen that a basic set of symmetries defines the essential band gap and connectivity. The remaining symmetry elements modify the band gap. The eleven lattices are classified into four fundamental topologies on the basis of the occupancy of high symmetry Wyckoff sites. Of the fundamental topologies studied, three display band gaps--- including two: the (F-RD) and a group 216 structure that have not been reported previously.


2003 ◽  
Vol 797 ◽  
Author(s):  
Natalya Tokranova ◽  
Bai Xu ◽  
James Castracane

Photonic crystals are periodic dielectric structures that have a photonic band gap to control the propagation of light in a certain wavelength range. This property offers a means to manipulate photons in the same way as electrons can be controlled in an atomic lattice. Porous silicon is an ideal candidate fo r the fabrication of photonic crystals because of the availability of a variety of silicon micromachining techniques. One-dimensional photonic crystals with customized parameters can be economically fabricated using porous silicon multilayer structures with periodically modulated porosity. Despite the structural non-homogeneities, porous silicon fabricated on a p-type Si substrate has optical properties similar to a dielectric material with a single effective refractive index. The exact value of the refractive index for each layer depends on its porosity. An engineered porosity can be obtained by changing the etching currents during the anodization process. This results in a modulation of the refractive index. A stack of alternating layers with high and low porosity produces a distributed Bragg reflector (DBR). Various designs incorporating multilayer porous silicon structures with an optical Fabry-Perot resonator and coupled microcavities are under development and can serve as an optical filter. Prototypes of such free-standing structures with 21–200 stacked layers to be used as DBRs, Fabry-Perot resonators or coupled microcavities are being fabricated. These structures are coated with polystyrenesulfonate on their backsides to increase mechanical strength and at the same time maintain flexibility. In this work, reflectance spectra of these porous silicon multilayers with and without polymer on the backside were measured. Simulations of the multilayer one-dimensional photonic crystals were performed to predic t the reflectance spectrum and optimize their structures before the fabrication and to compare to experimental data.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
J. V. Malik ◽  
K. D. Jindal ◽  
Vinay Kumar ◽  
Vipin Kumar ◽  
Arun Kumar ◽  
...  

The effect of the temperature and angle of incidence on the photonic band gap (PBG) for semiconductor-based photonic crystals has been investigated. The refractive index of semiconductor layers is taken as a function of temperature and wavelength. Three structures have been analyzed by choosing a semiconductor material for one of the two materials in a bilayer structure. The semiconductor material is taken to be ZnS, Si, and Ge with air in first, second, and third structures respectively. The shifting of band gaps with temperature is more pronounced in the third structure than in the first two structures because the change in the refractive index of Ge layers with temperature is more than the change of refractive index of both ZnS and Si layers with temperature. The propagation characteristics of the proposed structures are analyzed by transfer matrix method.


2007 ◽  
Vol 121-123 ◽  
pp. 179-182
Author(s):  
Shi Cheng Zhang ◽  
Jie Chen ◽  
Xing Guo Li

Nearly monodispersed SiO2 nanospheres, with different size and size standard deviation smaller than 5%, have been prepared by using batch/semibatch process. The SiO2 colloids were used as building blocks to self-assemble into the colloidal crystals, which photonic band gaps are close to the theoretical values, and can be modified by changing the size SiO2 nanospheres. With the increase of the size of SiO2 spheres, the photonic band gap red shift.


Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 651 ◽  
Author(s):  
Ermolaev ◽  
Kushnir ◽  
Sapoletova ◽  
Napolskii

Photonic crystals based on titanium oxide are promising for optoelectronic applications, for example as components of solar cells and photodetectors. These materials attract great research attention because of the high refractive index of TiO2. One of the promising routes to prepare photonic crystals based on titanium oxide is titanium anodizing at periodically changing voltage or current. However, precise control of the photonic band gap position in anodic titania films is a challenge. To solve this problem, systematic data on the effective refractive index of the porous anodic titanium oxide are required. In this research, we determine quantitatively the dependence of the effective refractive index of porous anodic titanium oxide on the anodizing regime and develop a model which allows one to predict and, therefore, control photonic band gap position in the visible spectrum range with an accuracy better than 98.5%. The prospects of anodic titania photonic crystals implementation as refractive index sensors are demonstrated.


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