scholarly journals Effect of Geometry on the Electromagnetic Wave Transport Properties of Photonic Crystals: Comparison of Top-Flat and Top-Curved Refractive Index Profiles

2021 ◽  
Author(s):  
M. Solaimani ◽  
malihe nejati
Keyword(s):  
Refractive Index ◽  
Electromagnetic Wave ◽  
Photonic Crystal ◽  
Photonic Crystals ◽  
Light Propagation ◽  
Refractive Index Profile ◽  
Physical Parameters ◽  
Index Profile ◽  
Wave Transport ◽  
Photonic Band

Abstract In the current paper, we try to engineer the refractive index profile in a one-dimensional photonic crystal as a powerful tool to manage the electromagnetic wave transmission properties. For this purpose, we have compared four sinusoidal, rectangular, triangular, and saw-tooth refractive index profile types. In this way, we have used a transfer matrix method accompanied by the discretization of the spatial domain. This method can readily be applied to any arbitrary continuous refractive index profile. Then, we have tried to address the effects of different geometrical and physical parameters, including the photonic crystal length L, dielectric permittivity εd, number of layers and plasma density np, etc. on the light propagation through the mentioned photonic crystals. In the proposed two-layer plasma/dielectric photonic crystals we could observe acceptable ranges of Omni-directional photonic band gaps that their position width and their number can be regulated. We determine the most and least tunable systems.

Omnidirectional reflector using linearly graded refractive index profile of 1D binary and ternary photonic crystal

Optik ◽  
2015 ◽  
Vol 126 (11-12) ◽  
pp. 1146-1149 ◽  
Author(s):  
Sanjeev Sharma ◽  
Rajendra Kumar ◽  
Kh.S. Singh ◽  
Arun Kumar ◽  
Vipin Kumar
Keyword(s):  
Refractive Index ◽  
Photonic Crystal ◽  
Refractive Index Profile ◽  
Index Profile ◽  
Ternary Photonic Crystal

Enhanced ODR range using exponentially graded refractive index profile of 1D binary photonic crystal

2016 ◽  
Author(s):  
Sanjeev Sharma ◽  
Rajendra Kumar ◽  
Kh. S. Singh ◽  
Deepti Jain ◽  
Arun Kumar
Keyword(s):  
Refractive Index ◽  
Photonic Crystal ◽  
Refractive Index Profile ◽  
Index Profile ◽  
Exponentially Graded

Photonic crystal fiber with W-type effective refractive index profile

Optik ◽  
2013 ◽  
Vol 124 (16) ◽  
pp. 2309-2312 ◽  
Author(s):  
Hongwei Chen ◽  
Shengping Chen ◽  
Jing Hou ◽  
Qisheng Lu
Keyword(s):  
Refractive Index ◽  
Photonic Crystal ◽  
Photonic Crystal Fiber ◽  
Effective Refractive Index ◽  
Refractive Index Profile ◽  
Index Profile ◽  
Crystal Fiber

scholarly journals Design and Analysis of a Photonic Crystal Based Biosensor Working at THz Frequency Region

2015 ◽  
Vol 62 (1) ◽  
pp. 7-9 ◽  
Author(s):  
Bratati Ghosh ◽  
Shukufe Rahman ◽  
Ahsan Habib ◽  
Subrata Das
Keyword(s):  
Refractive Index ◽  
Photonic Crystal ◽  
Photonic Crystals ◽  
Band Gap ◽  
Photonic Band Gap ◽  
Frequency Region ◽  
Maximum Sensitivity ◽  
The Relationship ◽  
Photonic Band

2D Photonic Crystal is investigated to find photonic band gap for the purpose of biosensing at THz frequency region. Several structures, one consisting of air holes in Si background and the others consisting of air holes filled with different analytes of having different Refractive Index (RI) in same Si background are considered. For each structure the change in photonic band gap due to the change in RI is observed and shown graphically. By comparing this plot with a standard chart of RI of different materials, any unknown biological analyte can be identified. Thus a biosensing method is developed by using the relationship between RI and band gap of photonic crystals. By comparing and calculating from the relationship; the maximum sensitivity of the developed biosensor is found to be 66.6%. DOI: http://dx.doi.org/10.3329/dujs.v62i1.21952 Dhaka Univ. J. Sci. 62(1): 7-9, 2014 (January)

scholarly journals MODELING OF MULTILAYER ULTRATHIN-FILM PHOTONIC CRYSTALS FOR SELECTIVE FILTERS

Doklady BGUIR ◽  
2019 ◽  
pp. 88-94
Author(s):  
L. S. Khoroshko ◽  
A. V. Baglov ◽  
A. A. Hnitsko
Keyword(s):  
Crystal Structure ◽  
Refractive Index ◽  
Liquid Crystal ◽  
Photonic Crystal ◽  
Photonic Crystals ◽  
Band Gap ◽  
Photonic Band Gap ◽  
Layer Structure ◽  
Half Wave ◽  
Photonic Band

The aim of the work was to study the optical properties of the one-dimensional photonic crystals from ultrathin alternating layers of titanium and silicon oxides with different order of alternating layers to form defective half-wave layers in the bulk of the photonic crystal. The layer thicknesses were optimized by the dispersion of the refractive index and it was shown that for the formation of 16-layer photonic crystal structure without a half-wave layer with a photonic band gap in the UV region, it is necessary to use layers of titanium dioxide and silicon oxide with a thickness of 28.3 and 53.2 nm, respectively. The structure of the 26-layer photonic crystal with a thickness of 2130 nm with two non-equidistant half-wave layers forming resonant transmission bands in the photonic band gap with peaks at 550 and 601 nm is proposed. Due to the dispersion of the refractive index, the ratio of the thicknesses of TiO2:SiO2 layers varies from 1:1.88 in the case of a 16-layer structure with a photonic band gap in the UV region to 1:1.5 in the case of a 26-layer structure with a photonic band gap in the visible range . The effect of a photonic crystal structure without half-wave layers on the emission spectrum of a liquid crystal display manufactured using IPS technology has been demonstrated in order to reduce the intensity of the blue component to increase the safety of the user's vision. The using of the photonic crystals with two half-wave defective layers allows to achieve complete separation of the spectrum components, which can be used to modify the spectra of large liquid crystal panels, their manufacture using AMOLED technology is a very difficult technological task even for leaders in this field.

Two-Dimensional Hybrid Photonic Crystal With Graded Low-Index Using a Nonuniform Voltage

2019 ◽  
Vol 75 (1) ◽  
pp. 65-71
Author(s):  
Behrooz Rezaei ◽  
Ibrahim Halil Giden ◽  
Mohammad Sadegh Zakerhamidi ◽  
Amid Ranjkesh ◽  
Tae-Hoon Yoon
Keyword(s):  
Refractive Index ◽  
Liquid Crystal ◽  
Photonic Crystal ◽  
Light Propagation ◽  
Near Field ◽  
Refractive Index Profile ◽  
Index Structure ◽  
Focal Distance ◽  
Graded Index ◽  
Gradient Refractive Index

AbstractWe proposed a new method for designing graded index lens using liquid crystal infiltration into annular photonic crystals. Applying an external nonuniform voltage in the transverse direction perpendicular to the direction of light propagation yields different orientation of liquid crystal molecules inside the photonic crystal unit cells. As a result, a gradient refractive index was modulated. We numerically investigate focusing properties of the designed graded index structure using plane-wave expansion and finite-difference time-domain methods. The gradient refractive index profile was adjusted by varying the nonuniform voltage excitations, which consequently altered the focal distance of the graded index structure. A wide tuning range of 1856 nm was achieved for focal distance by the proposed graded index structure. This feature can be implemented for planning a flat lens with tunable focal distance based on electro-optic effect. These achievements may have future applications in some optical devices such as near-field imaging and scanning.

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