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? 2021 Elsevier B.V.Manipulation of the refractive index has been of growing interest lately. We consider parameters and possibilities of enhancing the absolute-value limit of the linear index in coherent atomic systems. Starting ...
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? 2021 Elsevier B.V.Manipulation of the refractive index has been of growing interest lately. We consider parameters and possibilities of enhancing the absolute-value limit of the linear index in coherent atomic systems. Starting with a review of how two-level transitions – without and with added coherence effects – do not realistically allow for a significantly enhanced index at fixed atomic density, we discuss a possible way around this using wave mixing. This confirms that the only parameters, besides the medium optical depth/density, that can effectively change the value of the attainable index are the frequencies of the involved transitions.
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Refractive indices (n) have been experimentally determined for the binary liquid-liquid mixtures of Propylene carbonate (PC) (1) with benzene, ethylbenzene, o-xylene and p-xylene (2) at 298.15, 303.15 and 308.15 K over the entire ...
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Refractive indices (n) have been experimentally determined for the binary liquid-liquid mixtures of Propylene carbonate (PC) (1) with benzene, ethylbenzene, o-xylene and p-xylene (2) at 298.15, 303.15 and 308.15 K over the entire mole fraction range. The experimental values of n are utilised to calculate deviation in refractive index (Δn), molar refraction (R) and deviation in molar refraction (ΔR). A comparative study of Arago-Biot (A-B), Newton (NW), Eyring and John (E-J) equations for determining refractive index of a liquid has been carried out to test their validity for all the binary mixtures over the entire composition range at 298.15 K. Comparison of various mixing relations is represented in terms of average deviation (AVD). The An and ΔR values have been fitted to Redlich-Kister equation at 298.15 K and standard deviations have been calculated. The results are discussed in terms of intermolecular interactions present amongst the components.
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Sensitive materials are widely used in the field of optical fiber sensing because of their unique advantages such as rich types, controllable composition ratio and diverse structure distribution. In this paper, the surface of long...
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Sensitive materials are widely used in the field of optical fiber sensing because of their unique advantages such as rich types, controllable composition ratio and diverse structure distribution. In this paper, the surface of long-period fiber gratings with InGaZnO [(In2O3):(Ga2O3):(ZnO)] nano films with different compositions were coated by pulse laser deposition (PLD) technology. The best sensing ratio and the high sensitivity sensing of the refractive index of long-period fiber grating (LPFG) were achieved through the analysis of the influence of different ratios of InGaZnO nano films on the refractive index sensing characteristics of grating. High sensitivities of 337 nm/RIU (refractive index unit) and 145 dB/RIU of the LPFG are achieved when the best doping ratio of InGaZnO is 7:1:2.
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By suing V-prism refractometer, the refractive indices of a polyetherketone (PEK-c) guest-host polymer system were measured with the polymer in solutions. The Lorenz-Lorentz local field formalism was used in the calculation of the...
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By suing V-prism refractometer, the refractive indices of a polyetherketone (PEK-c) guest-host polymer system were measured with the polymer in solutions. The Lorenz-Lorentz local field formalism was used in the calculation of the refractive indices of the polymers from the measured indices of the polymer solutions and the pure solvent by using V-prism refractometer. The refractive index dispersions of the polymers were obtained by fitting the measured indices of the polymers to Sellmeyer equation. The method allows for an accuracy in index of 0.7 in the determination of the polymer indices. In addition, a large difference between the indices of the polymer and the solvent, and a higher polymer volume fraction in the measured polymer solution are favorable for a high accuracy.
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Theoretical calculations of emissivity difference, , with changing of water temperature from 301 to 279 K are performed at 820 cm-1 using the temperature-dependent refractive index of sea water recently proposed by Newman and co-w...
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Theoretical calculations of emissivity difference, , with changing of water temperature from 301 to 279 K are performed at 820 cm-1 using the temperature-dependent refractive index of sea water recently proposed by Newman and co-workers. The results are compared with the calculations using the temperature-dependent refractive index presented in 1977 by Pinkley and co-workers. The difference in between the two models is as small as 0.0003 for emission angles less than 30DG . At larger emission angles, the discrepancy in between the two models is notable. For example, are - 0.0055 and - 0.0070 for the Newman and Pinkley models, respectively, at an emission angle of 55DG . This discrepancy is mainly caused by the fact that the temperature dependence of the imaginary part of the refractive index of the Pinkley model is 1.5 times larger than that of the Newman model and the sea surface emissivity is significantly sensitive to the change of imaginary refractive index at this wavenumber. It is important that accurate values of the imaginary part of the refractive index be obtained.
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Electromagnetic surface modes present in one dimensional photonic crystals composed of left and right handed materials are determined by using the formalism of equivalent systems. It is found that surface waves in these systems ma...
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Electromagnetic surface modes present in one dimensional photonic crystals composed of left and right handed materials are determined by using the formalism of equivalent systems. It is found that surface waves in these systems may present notable differences against those modes found in completely dielectric photonic crystals, since they can be present inside the evanescent zone of the system as if they were cast out from the band of interface modes. These modes appear only in periodic systems that include left and right handed materials in the unit cell.
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An analytical model is presented for a rectangular lattice of isotropic scatterers with electric and magnetic resonances. Each isotropic scatterer is formed by putting appropriately 6 Omega-shaped perfectly conducting particles on...
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An analytical model is presented for a rectangular lattice of isotropic scatterers with electric and magnetic resonances. Each isotropic scatterer is formed by putting appropriately 6 Omega-shaped perfectly conducting particles on the faces of a cubic unit cell. A self-consistent dispersion equation is derived and then used to calculate correctly the effective permittivity and permeability in the frequency band where the lattice can be homogenized. The frequency range in which both the effective permittivity and permeability are negative corresponds to the mini-band of backward waves within the resonant band of the individual isotropic scatterer. (C) 2003 Elsevier Science B.V. All rights reserved. [References: 17]
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We explored backward waves propagating predominantly in a regular dielectric or even a vacuum. These modes emerge when a dielectric gap is made in a left-handed material, also known as a negative index material. As the gap becomes...
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We explored backward waves propagating predominantly in a regular dielectric or even a vacuum. These modes emerge when a dielectric gap is made in a left-handed material, also known as a negative index material. As the gap becomes nanometric in size, the modal pattern conforms with surface waves distribution and can exhibit either (or both) right-handed or left-handed characteristics. Interestingly, the details of the modal field in the gap is reminiscent of the plasmon polariton solutions of either a gap in metals (forward propagating) or a metal slab in a dielectric bulk (backward propagating). Subsequently, we examined a specific metamaterial realization of the left-handed optical medium by use of elongated nanometallic inclusions to generate positive-negative waveguide anisotropy. We used this metamaterial embedded between dielectric layers as the cladding layer of a gap and verified that the important results predicted above, namely nanometric-size backward waves, are obtained for this specific implementation.
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Visual data collection is paramount for the majority of scientific research. The added transparency of the zebrafish (Danio rerio) allows for a greater detail of complex biological research that accompanies seemingly simple observ...
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Visual data collection is paramount for the majority of scientific research. The added transparency of the zebrafish (Danio rerio) allows for a greater detail of complex biological research that accompanies seemingly simple observational tools. We developed a visual data analysis and collection approach that takes advantage of the cylindrical nature of the zebrafish allowing for an efficient and effective method for image capture that we call Specimen in a Corrected Optical Rotational Enclosure imaging. To achieve a nondistorted image, zebrafish were placed in a fluorinated ethylene propylene tube with a surrounding optically corrected imaging solution (water). By similarly matching the refractive index of the housing (fluorinated ethylene propylene tubing) to that of the inner liquid and outer liquid (water), distortion was markedly reduced, producing a crisp imagable specimen that is able to be fully rotated 360 degrees. A similar procedure was established for fixed zebrafish embryos using convenient, readily available borosilicate capillaries surrounded by 75% glycerol. The method described here could be applied to chemical genetic screening and other related high-throughput methods within the fish community and among other scientific fields
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We study the second-harmonic generation (SHG) in left-handed metamaterials with a quadratic nonlinear response. We demonstrate a novel type of the exact phase matching between the backward-propagating wave of the fundamental frequ...
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We study the second-harmonic generation (SHG) in left-handed metamaterials with a quadratic nonlinear response. We demonstrate a novel type of the exact phase matching between the backward-propagating wave of the fundamental frequency and the forward-propagating wave of the second harmonic (SH). We show that this novel parametric process can convert a surface of the left-handed metamaterial into an effective mirror that totally reflects the SH generated by an incident wave. We derive and analyze theoretically the coupled-mode equations for a semi-infinite nonlinear metamaterial. We also numerically study the SHG by a metamaterial slab of a finite thickness and reveal the existence of multistable nonlinear effects. (c) 2006 Optical Society of America.
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