scholarly journals Photonic Wannier-Stark Ladder from Coupled Electromagnetic Cavities

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Shahzad Anwar ◽  
Sucheng Li ◽  
Weixin Lu ◽  
Bo Hou
Keyword(s):  
Numerical Simulation ◽  
Refractive Index ◽  
Potential Effect ◽  
Analytical Derivation ◽  
Subwavelength Apertures ◽  
Frequency Spacing ◽  
Gradient Variation ◽  
Geometrical Series ◽  
Quantum Counterpart ◽  
Metallic Plates

We have investigated the photonic Wannier-Stark ladder in the system of coupled electromagnetic cavities, which consists of a stack of metallic plates structured with subwavelength apertures and where the tilted potential effect is mimicked by imposing the gradient variation of refractive index. Making an analogy to its quantum counterpart and assuming the translational property of its solutions, we have shown the photonic ladder has the eigenenergies, that is, frequencies, in a geometrical series. Within the approximation of small gradient, the ladder states manifest the equidistant frequency spacing in the spectrum. By both analytical derivation and numerical simulation, we have illustrated the geometrically progressed energies of the photonic Wannier-Stark ladder.

Manipulation of thermal radiation by using photonic crystals

2021 ◽  
pp. 2150262
Author(s):  
Azka Umar ◽  
Chun Jiang
Keyword(s):  
Numerical Simulation ◽  
Refractive Index ◽  
Photonic Crystal ◽  
Photonic Crystals ◽  
Thermal Emission ◽  
Heat Energy ◽  
Radiation Loss ◽  
One Dimensional ◽  
Waveguide Core ◽  
Low Refractive Index

This paper focuses on manipulating thermal emission and radiation loss of heat energy in a heat waveguide. A One-Dimensional Photonic Crystal is used as a waveguide clad to prohibit the thermal emission from escaping. The model may reduce the radiation loss of heat energy in the waveguide core, and heat energy can be confined to propagate along the waveguide’s longitude axis. The waveguide clad comprises alternative layers of high and low refractive index materials containing sufficient electromagnetic stop bands to trap the thermal emission from escaping out of the waveguide. The numerical simulation of the model shows that the forbidden bandgap of photonic crystal structures with alternative layers of silica and silicon has width enough to make heat energy be confined within the waveguide core so that efficient heat energy transmission can be achieved along the longitude axis of the waveguide.

Strong Exciton Polariton Dispersion in Multimode GaN Microcavity

2009 ◽  
Vol 1182 ◽  
Author(s):  
Mei-Chun Liu ◽  
Yuh-Jen Cheng ◽  
Shih-Hsin Hsu ◽  
Hao-Chung Kuo ◽  
Tien-Chang Lu ◽  
...  
Keyword(s):  
Refractive Index ◽  
Experimental Observation ◽  
Interaction Constant ◽  
Axial Mode ◽  
Photon Interaction ◽  
Frequency Spacing ◽  
Order Of Magnitude ◽  
Pl Spectrum

AbstractWe report the experimental observation of a very strong cavity polariton dispersion in a multi-axial mode GaN microcavity. The linewidth of photoluminescent (PL) spectrum covers a few cavity axial modes. The resonant photoluminescent peaks have a strong dispersion. The frequency spacing between adjacent peaks decreases by almost a factor of five from 470nm to 370nm. The strong dispersion can be well described by cavity polariton dispersion, but not by the dispersion of the refractive index of GaN. The measured exciton-photon interaction constant is 260 meV. It is an order of magnitude higher than the typically reported values for GaN microcavities

Design of a negative refractive index material based on numerical simulation

2016 ◽  
Vol 54 (4) ◽  
pp. 587-591 ◽  
Author(s):  
Muhammad Rizwan ◽  
Tariq Mahmood ◽  
H.M. Rafique ◽  
M. Tanveer ◽  
Syed Fawad Haider
Keyword(s):  
Numerical Simulation ◽  
Refractive Index ◽  
Negative Refractive Index ◽  
Refractive Index Material

Flexible chiral metamaterials with dynamically optical activity and high negative refractive index

2015 ◽  
Vol 29 (18) ◽  
pp. 1550087 ◽  
Author(s):  
Furkan Dincer ◽  
Muharrem Karaaslan ◽  
Emin Unal ◽  
Oguzhan Akgol ◽  
Cumali Sabah
Keyword(s):  
Numerical Simulation ◽  
Refractive Index ◽  
Numerical Analysis ◽  
Optical Activity ◽  
Negative Refractive Index ◽  
Experimental Results ◽  
Polarization Converter ◽  
Dynamic Design ◽  
Chiral Metamaterials ◽  
Good Agreement

We demonstrate numerically and experimentally chiral metamaterials (MTMs) based on gammadion-bilayer cross-wires that uniaxially create giant optical activity and tunable circular dichroism as a result of the dynamic design. In addition, the suggested structure gives high negative refractive index due to the large chirality in order to obtain an efficient polarization converter. We also present a numerical analysis in order to show the additional features of the proposed chiral MTM in detail. Therefore, a MTM sensor application of the proposed chiral MTM is introduced and discussed. The presented chiral designs offer a much simpler geometry and more efficient outlines. The experimental results are in a good agreement with the numerical simulation. It can be seen from the results that, the suggested chiral MTM can be used as a polarization converter, sensor, etc. for several frequency regimes.

Design of a novel negative refractive index material based on numerical simulation

2013 ◽  
Vol 63 (1) ◽  
pp. 10502 ◽  
Author(s):  
Muhammad Rizwan ◽  
Yan-Kun Dou ◽  
Hai-Bo Jin ◽  
Zhi-Ling Hou ◽  
Ling-Bao Kong ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Refractive Index ◽  
Negative Refractive Index ◽  
Refractive Index Material

scholarly journals Study of Black Silicon Wafer through Wet Chemical Etching for Parametric Optimization in Enhancing Solar Cell Performance by PC1D Numerical Simulation

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 881
Author(s):  
Md. Yasir Arafat ◽  
Mohammad Aminul Islam ◽  
Ahmad Wafi Bin Mahmood ◽  
Fairuz Abdullah ◽  
Tiong Sieh Kiong ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Refractive Index ◽  
Solar Cell ◽  
Doping Concentration ◽  
Anisotropic Etching ◽  
Cell Performance ◽  
Etching Process ◽  
Black Silicon ◽  
Solar Cell Performance ◽  
Wet Chemical

Black silicon (BSi) fabrication via surface texturization of Si-wafer in recent times has become an attractive concept regarding photon trapping and improved light absorption properties for photovoltaic applications. In this study, surface texturization has been conducted on mono-crystalline Si(100) wafer using a wet chemical anisotropic etching process with IPA:KOH solution to form micro-pyramidal surface structures. Moreover, the optimized properties of the fabricated BSi wafers are used for numerical simulation using PC1D software to analyze the performance of the solar cell and establish the correlation among relevant parameters. Effects such as doping concentration, texturization, passivation, and anti-reflection coating of BSi on the solar cell performance have numerically been investigated. Results show that textured surface obtained from the wet chemical anisotropic etching process has successfully reduced the reflectance of the BSi wafer and surpassed the solar cell efficiency by 2%, which is mainly attributed to the optical confinement of the textured pyramids on the surface with a height of 1–2 μm and angles of 70 degrees. Furthermore, the doping concentration of the p-type wafer and n-type emitter were optimized to be 1 × 1016 cm−3 and 1 × 1018 cm−3, respectively. In the case of device optimization, the SiO2 passivation layer with a refractive index of 1.48 and the Si3N4 ARC layer with a refractive index of 2.015 has been identified as the best combination for the solar cell performance. These optimized parameters eventually result in 23.14% conversion efficiency from numerical simulation for solar cells that use black silicon wafers as fabricated in this study.

Negative Refractive Index in a Two-Dimensional Nonlinear Rotator Lattice

2021 ◽  
Author(s):  
Lezheng Fang ◽  
Michael J. Leamy
Keyword(s):  
Numerical Simulation ◽  
Refractive Index ◽  
Direct Numerical Simulation ◽  
Incident Wave ◽  
Wave Amplitude ◽  
Multiple Scales ◽  
Negative Refractive Index ◽  
Index Of Refraction ◽  
Far Field ◽  
Negative Index

Abstract Acoustic metamaterials achieving negative index refraction usually operate linearly over a narrowband of frequency and consist of complex unit cell structures incorporating resonators. In this paper, we propose and analyze a simple, non-resonant, nonlinear rotator lattice structure which can be configured with either a positive or negative index of refraction over a broadband frequency range. The system’s frequency-dependent transmission is studied analytically via a reduced model along the interface of positive and negative refractive index lattices. Results for energy transmission are compared to those obtained using direct numerical simulation and close agreement is documented for small amplitude waves. For larger amplitude waves, a multiple scales analysis approach is used to show that the nonlinearity of the lattice shifts the system’s band structure, inducing amplitude-dependent transmission. For the studied system, the transmission decreases as we increase the incident wave amplitude, agreeing qualitatively with results from direct numerical simulation. At large-enough amplitudes, near the interface the wave amplitude decreases rapidly. As the wave travels further into the media, the amplitude drops, causing the nonlinear effect to decline as well. This decaying envelope does not result in a zero transmission in the far field, as expected from linear theory, and instead, the nonlinearity of the proposed rotator lattice prevents the far-field transmitted wave from surpassing a specific threshold amplitude, regardless of the incident wave. This finding may serve as an inspiration for designing nonlinear wave saturators.

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