Sharp bend in two-dimensional optical waveguide based on gradient refractive index structure

2017 ◽  
Vol 56 (19) ◽  
pp. 5336 ◽  
Author(s):  
Yinghui Cao ◽  
Raj Mittra ◽  
Zhenyu Liu ◽  
Jie Zheng
Keyword(s):  
Refractive Index ◽  
Optical Waveguide ◽  
Index Structure ◽  
Two Dimensional ◽  
Sharp Bend ◽  
Gradient Refractive Index

scholarly journals Energy Transfer Using Gradient Index Metamaterial

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Boopalan Ganapathy ◽  
Subramaniam Chittur Krishnaswamy
Keyword(s):  
Refractive Index ◽  
Energy Transfer ◽  
Spherical Wave ◽  
Beam Width ◽  
Horn Antenna ◽  
Index Structure ◽  
Side Lobe Level ◽  
Antenna Aperture ◽  
Gradient Refractive Index ◽  
Directive Gain

The gradient refractive index structure in this paper is used to increase the quantum of energy transfer. This is done by improving the directive gain of the pyramidal horn antenna at a frequency of 10 GHz. A three-dimensional array of closed square rings is placed in front of the horn antenna aperture to form a gradient refractive index structure. This structure increases the directive gain by 1.6 dB as compared to that of the conventional horn antenna. The structure nearly doubles the wireless power transfer quantum between the transmitter and the receiver when placed at both ends. The increase in the directivity is achieved by converting the spherical wave emanating from the horn to a plane wave once it passes through the structure. This transformation is realized by the gradient refractive index structure being placed perpendicular to the direction of propagation. The gradient refractive index is constructed by changing the dimensions of a closed square ring placed in the unit cell of the array. The change in the refractive index gives rise to an improvement of the half power beam width and side lobe level compared to that of the normal horn. The design and simulation were done using CST Studio software.

Two- and three-Dimensional Refractive Index Lattices Formed by Laterally Patterned Porous Silicon Layers

1999 ◽  
Vol 597 ◽  
Author(s):  
S. Uehara ◽  
H. Sasabu ◽  
K Taira ◽  
T. Hashimoto ◽  
T. Matsubara
Keyword(s):  
Refractive Index ◽  
Porous Silicon ◽  
Three Dimensional ◽  
Index Structure ◽  
Two Dimensional ◽  
Cladding Layer ◽  
Anodization Process ◽  
N Doping ◽  
Index Contrast ◽  
P Type

AbstractPorous silicon was used to fabricate refractive index lattices. Patterned n-doping and/ or substrate etching were used to introduce lateral periodicity. By anodizing p-type substrate with an n-doped area, we realized large refractive index contrast two-dimensional lattices with underlying cladding layer. The anodization process showed an effect specific to the small dimensional patterning and this effect has significant influence on the formed refractive index structure.

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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