scholarly journals Electrically Controlled Self-Focusing and Self-Localization in the Guided Channels

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1767
Author(s):  
Bing-Yau Huang ◽  
Yi-Hsiu Wu ◽  
Shuan-Yu Huang ◽  
Chie-Tong Kuo
Keyword(s):  
Refractive Index ◽  
Liquid Crystals ◽  
Coupling Effect ◽  
Experimental Results ◽  
Beam Polarization ◽  
Specific Design ◽  
Photonic Circuits ◽  
Self Focusing ◽  
Operation Modes ◽  
Beam Coupling

In this paper, we demonstrate the potential of liquid crystals (LCs) on the applications of small, simple, and tunable optical guided channels. Experimental results show that three operation modes of beam coupling can be achieved, depending on the feature of the electrically controllable refractive index, the incident position, and the specific design of electrodes. The dependence of the beam polarization on self-focusing and coupling effect are also discussed. The electrically controllable self-focusing and beam coupling are highly potential on integrated photonic circuits.

scholarly journals Voltage-Controllable Guided Propagation in Nematic Liquid Crystals

2018 ◽  
Vol 2018 ◽  
pp. 1-4
Author(s):  
Hsin-Yu Yao ◽  
Shang-Min Yeh
Keyword(s):  
Refractive Index ◽  
Liquid Crystals ◽  
Single Channel ◽  
Coupling Effect ◽  
Nematic Liquid Crystals ◽  
The Self ◽  
External Voltage ◽  
Self Focusing ◽  
Guided Propagation ◽  
Adjacent Channels

Voltage-controllable guided channels are formed in a planar nematic liquid crystals cell. The director of liquid crystals can be aligned by applying external voltage, which results in a difference of the refractive index between two adjacent channels; therefore, the incidence beam can be coupled from one channel to another. First, we discussed the propagation of the beam and the self-focusing in a single channel; then we discussed the propagation of the beam and the coupling effect in the two channels. The results showed that the propagation of the beam can be selected in each channel by applying voltages in the two individual electrode channels.

ANALYSIS OF OPTICALLY INDUCED REFRACTIVE INDEX CHANGE OF DYE-DOPED NEMATIC LIQUID CRYSTALS

2002 ◽  
Vol 11 (01) ◽  
pp. 1-12 ◽  
Author(s):  
A. SHISHIDO ◽  
M.-Y. SHIH ◽  
I. C. KHOO
Keyword(s):  
Refractive Index ◽  
Liquid Crystals ◽  
Diffraction Efficiency ◽  
Order Parameter ◽  
Nematic Liquid Crystals ◽  
Refractive Index Change ◽  
Beam Polarization ◽  
Methyl Red ◽  
Parameter Modification ◽  
Index Changes

We present a detailed quantitative experimental and theoretical study of laser induced refractive index changes in nematic liquid crystals doped with methyl-red, disperse red and azobenzene liquid crystal. These refractive index changes, originating from molecular reorientations and order parameter modification, are measured by means of intensity and polarization grating methods. The reorientation of the director axis is calculated from polarization dependence of the probe beam diffraction efficiency. The contribution of each effect to the total diffraction efficiency is quantitatively evaluated. In general, we found that the reorientational direction of the NLC molecules depends on the dopants as well as the nature of the pump beam polarization state. In methyl-red doped samples, the laser induced reorientation mechanism dominates, whereas order parameter modification plays a major role in the others.

scholarly journals Nonlinear refractive index of porcine cornea studied by z-scan and self-focusing during femtosecond laser processing

2010 ◽  
Vol 18 (4) ◽  
pp. 3700 ◽  
Author(s):  
M. Miclea ◽  
U. Skrzypczak ◽  
S. Faust ◽  
F. Fankhauser ◽  
H. Graener ◽  
...  
Keyword(s):  
Refractive Index ◽  
Femtosecond Laser ◽  
Nonlinear Refractive Index ◽  
Laser Processing ◽  
Self Focusing ◽  
Femtosecond Laser Processing ◽  
Porcine Cornea

Relativistic self-focusing of a rippled laser beam in a plasma

1999 ◽  
Vol 62 (4) ◽  
pp. 389-396 ◽  
Author(s):  
M. V. ASTHANA ◽  
A. GIULIETTI ◽  
DINESH VARSHNEY ◽  
M. S. SODHA
Keyword(s):  
Refractive Index ◽  
Laser Beam ◽  
The Self ◽  
Laser Beams ◽  
Radial Dependence ◽  
Main Beam ◽  
Gaussian Laser Beam ◽  
Self Focusing ◽  
Saturation Effects ◽  
Paraxial Ray

This paper presents an analysis of the relativistic self-focusing of a rippled Gaussian laser beam in a plasma. Considering the nonlinearity as arising owing to relativistic variation of mass, and following the WKB and paraxial-ray approximations, the phenomenon of self-focusing of rippled laser beams is studied for arbitrary magnitude of nonlinearity. Pandey et al. [Phys. Fluids82, 1221 (1990)] have shown that a small ripple on the axis of the main beam grows very rapidly with distance of propagation as compared with the self-focusing of the main beam. Based on this analogy, we have analysed relativistic self-focusing of rippled beams in plasmas. The relativistic intensities with saturation effects of nonlinearity allow the nonlinear refractive index in the paraxial regime to have a slower radial dependence, and thus the ripple extracts relatively less energy from its neighbourhood.

scholarly journals Improved Refractive Index Sensitivity Utilizing Long-Period Gratings with Periodic Corrugations on Cladding

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Anthony Lim ◽  
Wen Bin Ji ◽  
Swee Chuan Tjin
Keyword(s):  
Refractive Index ◽  
Cost Effective ◽  
Experimental Results ◽  
Refractive Index Sensitivity ◽  
Long Period ◽  
Specimen Collection ◽  
Long Period Gratings ◽  
Highly Sensitive ◽  
Index Sensitivity

A new structure of Long-Period Gratings (LPGs) sensor is introduced as a sensitive ambient RI sensor. This structure consists of creating periodic corrugations on the cladding of the LPG. The experimental results show that this LPG structure has good performances in terms of linearity and sensitivity and serves as a highly sensitive and cost-effective sensor. It also has the advantage of portability as the corrugation can also serve as the reservoir for the specimen collection to be tested.

scholarly journals Parallel LC shaped metamaterial resonator for C and X band satellite applications with wider bandwidth

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Rashed Iqbal Faruque ◽  
Air Mohammad Siddiky ◽  
Eistiak Ahamed ◽  
Mohammad Tariqul Islam ◽  
Sabirin Abdullah
Keyword(s):  
Refractive Index ◽  
Negative Refractive Index ◽  
Coupling Effect ◽  
Research Work ◽  
Negative Permittivity ◽  
Electromagnetic Properties ◽  
Conducting Layer ◽  
Resonant Frequencies ◽  
New Era ◽  
Satellite Applications

AbstractThe electromagnetic properties of the metal based dielectric in the field of millimeter and sub-millimeter technology attracts a new era for innovation. In this research work, we have introduced a parallel LC shaped metamaterial resonator with wider bandwidth. The negative refractive index for two resonant frequencies is located from the negative permittivity from 5.1 to 6.3, 10.4 to 12.9 GHz, where the negative refractive index is located from 5.4 to 6.3 and 10.5 to 13.5 GHz. The electromagnetic wave polarizing in the proposed structure with parallel LC shaped metallic structure shows a fascinating response of wider bandwidth for the external electric and magnetic field. This paper focuses on the design of conducting layer for the suggested design with the parallel metallic arm for analysing the mutual coupling effect of the scattering response where the sub-branch in metallic design is shown more resonant frequencies with the enhancement of the compactness. This proposed structure is analysed with different metallic arrangements and array structures for different boundary conditions.

scholarly journals Influence of Hydrostatic Pressure and Cationic Type on the Diffusion Behavior of Chloride in Concrete

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2851
Author(s):  
Huanqiang Liu ◽  
Linhua Jiang
Keyword(s):  
Diffusion Coefficient ◽  
Hydrostatic Pressure ◽  
Diffusion Model ◽  
Coupling Effect ◽  
Experimental Results ◽  
Chloride Diffusion ◽  
Concrete Durability ◽  
Chloride Diffusion Coefficient ◽  
Diffusion Behavior ◽  
Diffusion Source

The durability of the concrete in underground and marine engineering is affected by the underground and ocean environment. Chloride diffusion coefficient under hydrostatic pressure is a key parameter of concrete durability design under corresponding conditions. Therefore, this paper studies the diffusion behavior of chloride in different diffusion source solutions by experiment and simulation. Based on the experimental results, this paper proposes a new chloride diffusion model under the coupling effect of diffusion and convection. The interaction of ions and compounds in the diffusion source solutions, concrete pore fluid, and concrete material are considered in the new chloride diffusion model. The experimental results show that chloride diffusion rate is significantly affected by hydrostatic pressure, which increases with the increase of hydrostatic pressure. The chloride diffusion coefficient shows a certain difference in difference diffusion source solutions. The chloride diffusion coefficient in divalent cationic diffusion source solutions is the largest, the chloride diffusion coefficient in the divalent and monovalent cationic compound ones is in the middle, and the chloride diffusion coefficient in the monovalent cationic ones is the smallest. There is a linear relationship between the chloride diffusion coefficient and the hydrostatic pressure whether in single or combined cationic diffusion source solutions.

Nonlinear Refractive Index of Silicon Nanoparticles: A Short Review

2014 ◽  
Vol 1 (2) ◽  
pp. 87-97
Author(s):  
Sudakshina Prusty
Keyword(s):  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Phase Modulation ◽  
Silicon Nanoparticles ◽  
Nonlinear Coefficient ◽  
Short Review ◽  
Self Phase Modulation ◽  
Physical Mechanisms ◽  
Self Focusing ◽  
Physical Phenomena

This article discusses the nonlinear refractive index of silicon nanoparticles starting from the basic formalism to some of the consequent physical phenomena like self focusing and self phase modulation. Several experimental techniques mainly based on Z-scan are discussed to measure the nonlinear refractive index. Another less explored technique for silicon nanoparticles, which studies the far-field optical fringe pattern formed by spatial self-phase modulation, is also discussed. Computation of the nonlinear refractive index is shown in detail by employing these two techniques. While Z-scan can estimate the nonlinear coefficient of a medium in a chosen time scale, the optical fringe method can predict the overall nonlinear refractive index due to all possible physical mechanisms. Some of the recent results for silicon nanoparticles using these two techniques are also discussed.

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