Research on electromagnetic properties of near-zero refractive index metamaterials

2020 ◽  
Author(s):  
Xianyu Shen ◽  
Yusong Feng ◽  
Jianrong Li ◽  
Yuan Lu
Keyword(s):  
Refractive Index ◽  
Electromagnetic Properties

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.

Coating Thickness Characterization of Composite Materials Using Terahertz Waves

2016 ◽  
Vol 878 ◽  
pp. 70-73 ◽  
Author(s):  
Kwang Hee Im ◽  
Sun Kyu Kim ◽  
David K. Hsu ◽  
Jong An Jung
Keyword(s):  
Refractive Index ◽  
Coating Thickness ◽  
Composite Laminates ◽  
Electromagnetic Properties ◽  
Terahertz Waves ◽  
Reflection Mode ◽  
Cfrp Composite ◽  
Spectroscopy System ◽  
Terahertz Ray

Recently, terahertz ray imaging has emerged as one of the most promising new powerful nondestructive evaluation (NDE) techniques for the area applications. In this study, a new time-domain spectroscopy system was utilized for measuring the coating thickness on CFRP composite laminates. Extensive experimental measurements in reflection mode were made to map out the T-ray images. Also, the refractive index was estimated based on the electromagnetic properties. The CFRP composite laminates were observed in reflection mode and limitations will be discussed in the T-ray processing. By using these characterized material properties, the characteristics was successfully demonstrated for T-ray behavior propagating through the Shim Stock films for acquiring the refractive index. The T-ray technique has been developed for the measurement of the thickness of the Shim Stock films and the coating thickness on CFRP composites. Good results have been obtained in tests made on the thickness of the standard film samples with the coating thickness ranging from around hundreds of μm.

RESERVOIR EFFECT ON A FOUR-LEVEL LEFT-HANDED SYSTEM

2014 ◽  
Vol 28 (04) ◽  
pp. 1450024
Author(s):  
N. BOUTABBA
Keyword(s):  
Refractive Index ◽  
Negative Refractive Index ◽  
Negative Permittivity ◽  
Electromagnetic Properties ◽  
Thermal Bath ◽  
Potential Candidate ◽  
Left Handed ◽  
Atomic Medium ◽  
Coupling Strengths ◽  
Domain Of Parameters

In this paper, we theoretically analyze the electromagnetic properties of a negative refractive index medium configured as a four-level system under thermal bath effect. For different thermal bath coupling strengths, the system shows negative permittivity and permeability as well as a large negative refractive index. This atomic medium is stable against environmental effect in a large experimental reachable domain of parameters which makes it a potential candidate for important applications.

scholarly journals Terahertz Optics of Materials with Spatially Harmonically Distributed Refractive Index

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5208
Author(s):  
Dzmitry Bychanok ◽  
Gleb Gorokhov ◽  
Artyom Plyushch ◽  
Alfredo Ronca ◽  
Marino Lavorgna ◽  
...  
Keyword(s):  
Refractive Index ◽  
Thermoplastic Polyurethane ◽  
Electromagnetic Properties ◽  
Electromagnetic Response ◽  
Frequency Range ◽  
Spatially Periodic ◽  
3D Printed ◽  
New Generation ◽  
Analytical Expressions ◽  
Theoretical Results

The electromagnetic properties of structures with spatially periodic distributed graded refractive index were investigated in the terahertz frequency range. The band structure and electromagnetic response of material with harmonically distributed refractive index were calculated and analyzed. The analytical expressions for frequencies of the first and second bandgap are derived. 3D printed gyroid based architectures were proven to be harmonically graded refractive index structures with designed bandgaps in THz frequency ranges. The transmission coefficient of thermoplastic polyurethane-based samples were experimentally measured in the frequency range 100–500 GHz and compared with theoretical results. Due to losses in the real world produced samples, the predicted response is significantly dumped in the terahertz range and only traces of band gaps are experimentally observed. This funding paves the way toward a new generation of 3D printed THz components for gradient-index optics applications.

scholarly journals THz-TDS Techniques of Thickness Measurements in Thin Shim Stock Films and Composite Materials

2021 ◽  
Vol 11 (19) ◽  
pp. 8889
Author(s):  
Kwang-Hee Im ◽  
Sun-Kyu Kim ◽  
Young-Tae Cho ◽  
Yong-Deuck Woo ◽  
Chien-Ping Chiou
Keyword(s):  
Refractive Index ◽  
Time Of Flight ◽  
Thickness Measurement ◽  
Terahertz Wave ◽  
Electromagnetic Properties ◽  
Gfrp Composites ◽  
Ray Method ◽  
Reinforced Plastics ◽  
Resonance Frequencies ◽  
Thickness Measurements

Terahertz wave (T-ray) scanning applications are one of the most promising tools for nondestructive evaluation. T-ray scanning applications use a T-ray technique to measure the thickness of both thin Shim stock films and GFRP (glass fiber-reinforced plastics) composites, of which the samples were selected because the T-ray method could penetrate the non-conducting samples. Notably, this method is nondestructive, making it useful for analyzing the characteristics of the materials. Thus, the T-ray thickness measurement can be found for both non-conducting Shim stock films and GFRP composites. In this work, a characterization procedure was conducted to analyze electromagnetic properties, such as the refractive index. The obtained estimates of the properties are in good agreement with the known data for poly methyl methacrylate (PMMA) for acquiring the refractive index. The T-ray technique was developed to measure the thickness of the thin Shim stock films and the GFRP composites. Our tests obtained good results on the thickness of the standard film samples, with the different thicknesses ranging from around 120 μm to 500 μm. In this study, the T-ray method was based on the reflection mode measurement, and the time-of-flight (TOF) and resonance frequencies were utilized to acquire the thickness measurements of the films and GFRP composites. The results showed that the thickness of the samples of frequency matched those obtained directly by time-of-flight (TOF) methods.

TEM characterization of proton-exchanged LiNbO3 optical waveguides

1986 ◽  
Vol 44 ◽  
pp. 480-481
Author(s):  
W. E. Lee
Keyword(s):  
Refractive Index ◽  
Benzoic Acid ◽  
Optical Waveguides ◽  
Total Internal Reflection ◽  
Index Of Refraction ◽  
Optical Measurements ◽  
Lithium Ions ◽  
Wide Channel ◽  
Tem Characterization

An optical waveguide consists of a several-micron wide channel with a slightly different index of refraction than the host substrate; light can be trapped in the channel by total internal reflection.Optical waveguides can be formed from single-crystal LiNbO3 using the proton exhange technique. In this technique, polished specimens are masked with polycrystal1ine chromium in such a way as to leave 3-13 μm wide channels. These are held in benzoic acid at 249°C for 5 minutes allowing protons to exchange for lithium ions within the channels causing an increase in the refractive index of the channel and creating the waveguide. Unfortunately, optical measurements often reveal a loss in waveguiding ability up to several weeks after exchange.

Facet Topography and Dislocation Structure as a Possible Source for Electrical Heterogeneity in [001] TILT Bicrystals of YBa2Cu3O7-δ

1996 ◽  
Vol 54 ◽  
pp. 338-339
Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Electromagnetic Properties ◽  
Length Scale ◽  
Density Values ◽  
Current Densities ◽  
Applied Fields ◽  
A Current

A current theme in the study of the critical current density behavior of YBa2Cu3O7-δ (YBCO) grain boundaries is that their electromagnetic properties are heterogeneous on various length scales ranging from 10s of microns to ˜ 1 Å. Recently, combined electromagnetic and TEM studies on four flux-grown bicrystals have demonstrated a direct correlation between the length scale of the boundaries’ saw-tooth facet configurations and the apparent length scale of the electrical heterogeneity. In that work, enhanced critical current densities are observed at applied fields where the facet period is commensurate with the spacing of the Abrikosov flux vortices which must be pinned if higher critical current density values are recorded. To understand the microstructural origin of the flux pinning, the grain boundary topography and grain boundary dislocation (GBD) network structure of [001] tilt YBCO bicrystals were studied by TEM and HRTEM.

Light microscopy of ceramics

1993 ◽  
Vol 51 ◽  
pp. 908-909
Author(s):  
Walter C. McCrone
Keyword(s):  
Refractive Index ◽  
Light Microscopy ◽  
Light Microscope ◽  
Polarized Light ◽  
Refractive Indices ◽  
Complete Coverage ◽  
The Subject ◽  
Lower Refractive Index

An excellent chapter on this subject by V.D. Fréchette appeared in a book edited by L.L. Hench and R.W. Gould in 1971 (1). That chapter with the references cited there provides a very complete coverage of the subject. I will add a more complete coverage of an important polarized light microscope (PLM) technique developed more recently (2). Dispersion staining is based on refractive index and its variation with wavelength (dispersion of index). A particle of, say almandite, a garnet, has refractive indices of nF = 1.789 nm, nD = 1.780 nm and nC = 1.775 nm. A Cargille refractive index liquid having nD = 1.780 nm will have nF = 1.810 and nC = 1.768 nm. Almandite grains will disappear in that liquid when observed with a beam of 589 nm light (D-line), but it will have a lower refractive index than that liquid with 486 nm light (F-line), and a higher index than that liquid with 656 nm light (C-line).

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