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.

Negative Refractive Index Materials

2006 ◽  
Vol 3 (2) ◽  
pp. 189-218 ◽  
Author(s):  
Victor Veselago ◽  
Leonid Braginsky ◽  
Valery Shklover ◽  
Christian Hafner
Keyword(s):  
Photonic Crystals ◽  
Negative Refraction ◽  
Negative Refractive Index ◽  
Index Of Refraction ◽  
Negative Index ◽  
Practical Applications ◽  
The Third ◽  
Left Handed ◽  
Negative Index Of Refraction ◽  
History Of

The main directions of studies of materials with negative index of refraction, also called left-handed or metamaterials, are reviewed. First, the physics of the phenomenon of negative refraction and the history of this scientific branch are outlined. Then recent results of studies of photonic crystals that exhibit negative refraction are discussed. In the third part numerical methods for the simulation of negative index material configurations and of metamaterials that exhibit negative index properties are presented. The advantages and the shortages of existing computer packages are analyzed. Finally, details of the fabrication of different kinds of metamaterials are given. This includes composite metamaterials, photonic crystals, and transmission line metamaterials for different wavelengths namely radio frequencies, microwaves, terahertz, infrared, and visible light. Furthermore, some examples of practical applications of metamaterials are presented.

Effect of wave amplitude on turbulent flow in a wavy channel by direct numerical simulation

2009 ◽  
Vol 36 (9-10) ◽  
pp. 697-707 ◽  
Author(s):  
H.S. Yoon ◽  
O.A. El-Samni ◽  
A.T. Huynh ◽  
H.H. Chun ◽  
H.J. Kim ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Turbulent Flow ◽  
Wave Amplitude ◽  
Wavy Channel

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 Negative-Index Materials: Optics by Design

MRS Bulletin ◽  
2008 ◽  
Vol 33 (10) ◽  
pp. 907-914 ◽  
Author(s):  
Wounjhang Park ◽  
Jinsang Kim
Keyword(s):  
Recent Progress ◽  
Periodic Structures ◽  
Negative Refractive Index ◽  
Intrinsic Property ◽  
Index Of Refraction ◽  
Negative Permittivity ◽  
Negative Index ◽  
Acoustic Metamaterials ◽  
Negative Index Materials ◽  
Materials Research

AbstractIndex of refraction, a fundamental optical constant that enters in the descriptions of almost all optical phenomena, has long been considered an intrinsic property of a material. However, the recent progress in negative-index material (NIM) research has shown that the utilization of deep-subwavelength-scale features can provide a means to engineer fundamental optical constants such as permittivity, permeability, impedance, and index of refraction. Armed with new nanofabrication techniques, researchers worldwide have developed and demonstrated a variety of NIMs. One implementation uses a combination of electric and magnetic resonators that simultaneously produce negative permittivity and permeability, and consequently negative refractive index. Others involve chirality, anisotropy, or Bragg resonance in periodic structures. NIM research is the beginning of new optical materials research in which the desired optical properties and functionalities are artificially generated. Clearly, creating negative index materials is not the only possibility, and the most recent developments explore new realms of materials with near-zero indexes and inhomogeneous index profiles that can produce novel phenomena such as invisibility. Furthermore, the concept of controlling macroscopic material properties with a composite structure containing subwavelength-scale features extends to the development of acoustic metamaterials. By providing a review of recent progress in NIM research, we hope to share the excitement of the field with the broader materials research community and also to spur new ideas and research directions.

Negative index from asymmetric metallic cut wire pairs metamaterials

2009 ◽  
Vol 1 (6) ◽  
pp. 521-527 ◽  
Author(s):  
Shah Nawaz Burokur ◽  
André de Lustrac
Keyword(s):  
Refractive Index ◽  
Material Properties ◽  
Negative Refractive Index ◽  
Negative Permittivity ◽  
Inversion Method ◽  
Experimental Measurements ◽  
Negative Index ◽  
Transmission And Reflection

Metamaterials made of exclusively metallic cut wire pairs have been experimentally demonstrated to exhibit a negative refractive index at optical frequencies. However, other related works on slightly different wire and plate pairs have not shown a negative index. In this paper, we present the analogy between previously reported S-shaped metamaterials and asymmetric cut wire pairs by a simple unifying approach. These two structures present a negative index for some geometrical configurations. Using simulations and experimental measurements in the microwave domain, we investigate the material properties of the last structure. Applying the inversion method from transmission and reflection responses, we show that a negative index is exhibited due to simultaneous negative permittivity ε and permeability μ. A negative index n is experimentally verified in a bulk prism engineered by stacking several layers of the metamaterial.

scholarly journals Direct numerical simulation of a self-similar adverse pressure gradient turbulent boundary layer at the verge of separation

2017 ◽  
Vol 829 ◽  
pp. 392-419 ◽  
Author(s):  
V. Kitsios ◽  
A. Sekimoto ◽  
C. Atkinson ◽  
J. A. Sillero ◽  
G. Borrell ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Reynolds Number ◽  
Direct Numerical Simulation ◽  
Pressure Gradient ◽  
Adverse Pressure Gradient ◽  
Streamwise Velocity ◽  
Far Field ◽  
Self Similar ◽  
The Mean

The statistical properties are presented for the direct numerical simulation of a self-similar adverse pressure gradient (APG) turbulent boundary layer (TBL) at the verge of separation. The APG TBL has a momentum thickness-based Reynolds number range from $Re_{\unicode[STIX]{x1D6FF}_{2}}=570$ to 13 800, with a self-similar region from $Re_{\unicode[STIX]{x1D6FF}_{2}}=10\,000$ to 12 300. Within this domain the average non-dimensional pressure gradient parameter $\unicode[STIX]{x1D6FD}=39$, where for a unit density $\unicode[STIX]{x1D6FD}=\unicode[STIX]{x1D6FF}_{1}P_{\!e}^{\prime }/\unicode[STIX]{x1D70F}_{w}$, with $\unicode[STIX]{x1D6FF}_{1}$ the displacement thickness, $\unicode[STIX]{x1D70F}_{w}$ the mean shear stress at the wall and $P_{\!e}^{\prime }$ the far-field pressure gradient. This flow is compared with previous zero pressure gradient and mild APG TBL ($\unicode[STIX]{x1D6FD}=1$) results of similar Reynolds number. All flows are generated via the direct numerical simulation of a TBL on a flat surface with far-field boundary conditions tailored to apply the desired pressure gradient. The conditions for self-similarity, and the appropriate length and velocity scales, are derived. The mean and Reynolds stress profiles are shown to collapse when non-dimensionalised on the basis of these length and velocity scales. As the pressure gradient increases, the extent of the wake region in the mean streamwise velocity profiles increases, whilst the extent of the log-layer and viscous sublayer decreases. The Reynolds stress, production and dissipation profiles of the APG TBL cases exhibit a second outer peak, which becomes more pronounced and more spatially localised with increasing pressure gradient. This outer peak is located at the point of inflection of the mean velocity profiles, and is suggestive of the presence of a shear flow instability. The maximum streamwise velocity variance is located at a wall normal position of $\unicode[STIX]{x1D6FF}_{1}$ of spanwise wavelength of $2\unicode[STIX]{x1D6FF}_{1}$. In summary as the pressure gradient increases the flow has properties less like a zero pressure gradient TBL and more akin to a free shear layer.

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