Geometrical parameters controlled focusing and enhancing near field in infinite circular metal-dielectric multilayered cylinder

2013 ◽  
Vol 102 (12) ◽  
pp. 123107 ◽  
Author(s):  
Shaoyan Gao ◽  
Pengbo Li ◽  
Fuli Li
Keyword(s):  
Near Field ◽  
Geometrical Parameters ◽  
Multilayered Cylinder

scholarly journals Optical bistability in two-dimensional nonlinear composites of coated cylinders with nonlinear core and graded shell

2020 ◽  
Vol 7 ◽  
pp. 6
Author(s):  
Ya M. Wu ◽  
Guo Q. Chen ◽  
Wen C. Wu ◽  
Yi X. Wang ◽  
Yang Huang
Keyword(s):  
Optical Bistability ◽  
Near Field ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Geometrical Parameters ◽  
Core Radius ◽  
The Core ◽  
Nonlinear Composite ◽  
Incident Frequency

The intrinsic optical bistability of the nonlinear composite consisting of coated cylinders with nonlinear core and graded Drude shell is investigated with self-consistent mean-field approximation. We derive the nonlinear equation of near field for such graded composite in the quasistatic limit. We demonstrate that the bistability threshold and the bistable width are highly dependent on the core radius, the incident frequency, and the graded coefficient of the coated cylinder inclusion. It is found that the optical bistability appears only when the core radius and the incident frequency satisfy some specific conditions. Therefore, the optical bistability for nonlinear composite materials may be optimized by the suitable adjustment of the physical and geometrical parameters. Our results may be helpful for the design of the nonlinear device with appropriate bistability.

Robust Nanoscale Patterns for Thin Film Solar Cells Using Inverse Optimization of Nonuniformly Sampled Absorption Spectrum

2011 ◽  
Author(s):  
Shima Hajimirza ◽  
John R. Howell
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Near Field ◽  
Solar Spectrum ◽  
Sampling Technique ◽  
Optimization Techniques ◽  
Photon Absorption ◽  
Absorption Enhancement ◽  
Geometrical Parameters ◽  
Sensitivity Assessment

This paper outlines several techniques for systematic and efficient optimization as well as sensitivity assessment to fabrication tolerances of surface texturing patterns in thin film amorphous silicon (a-Si) solar cells. The aim is to achieve maximum absorption enhancement. We report the joint optimization of several geometrical parameters of a three dimensional lattice of periodic square silver nanoparticles, and an absorbing thin layer of a-Si, using constraint optimization tools and numerical FDTD simulations. Global and local optimization methods, such as the Broyden–Fletcher–Goldfarb–Shanno Quasi-Newton (BFGS-QN) and Simulated Annealing (SA) are employed concurrently for solving the inverse near field radiation problem. The design of the silver patterned solar panel is optimized to yield maximum average enhancement in photon absorption over the solar spectrum. The optimization techniques are expedited and improved by using a novel nonuniform adaptive spectral sampling technique. Furthermore, the sensitivity of the optimally designed parameters of the solar structure is analyzed by postulating a probabilistic model for the errors introduced in the fabrication process. Monte Carlo (MC) simulations and Unscented Transform (UT) techniques are used for this purpose.

scholarly journals Modeling of Optical Nanoantennas

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Bedir B. Yousif ◽  
Ahmed S. Samra
Keyword(s):  
Data Storage ◽  
Spectral Response ◽  
Near Field ◽  
Approximation Error ◽  
Field Enhancement ◽  
Optical Data Storage ◽  
Optical Data ◽  
Localized Surface Plasmon ◽  
Geometrical Parameters ◽  
Strong Light

The optical properties of plasmonic nanoantennas are investigated in detail using the finite integration technique (FIT). The validity of this technique is verified by comparison to the exact solution generalized Mie method (GMM). The influence of the geometrical parameters (antenna length, gap dimension, and shapes) on the antenna field enhancement and spectral response is discussed. Localized surface plasmon resonances of Au (gold) dimers nanospheres, bowtie, and aperture bowtie nanoantennas are modeled. The enhanced field is equivalent to a strong light spot which can lead to the resolution improvement of the microscopy and optical lithography, thus increasing the optical data storage capacity. Furthermore, the sensitivity of the antennas to index changes of the environment and substrate is investigated in detail for biosensing applications. We confirm that our approach yields an exact correspondence with GMM theory for Au dimers nanospheres at gap dimensions 5 nm and 10 nm but gives an approximation error of less than 1.37% for gap dimensions 1 nm and 2 nm with diameters approaching 80 nm. In addition, the far-field characteristics of the aperture bowtie nanoantenna such as directivity and gain are studied. The promising results of this study may have useful potential applications in near-field sample detection, optical microscopy, and so forth.

scholarly journals Broadband Dipole-Loop Combined Nanoantenna Fed by Two-Wire Optical Transmission Line

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Janilson L. de Souza ◽  
Karlo Q. da Costa ◽  
Victor Dmitriev ◽  
Felipe Bamberg
Keyword(s):  
Reflection Coefficient ◽  
Transmission Line ◽  
Radiation Pattern ◽  
Method Of Moments ◽  
Input Impedance ◽  
Optical Transmission ◽  
Near Field ◽  
Impedance Matching ◽  
Linear Method ◽  
Geometrical Parameters

This paper presents a broadband nanoantenna fed by a two-wire optical transmission line (OTL). The antenna is defined by a combination of a dipole and a loop, where only the dipole element is connected to the OTL. The analysis is fulfilled by the linear method of moments with equivalent surface impedance to model the conductors. Firstly, the nanoantenna alone is investigated, where the input impedance, current distribution, reflection coefficient, fractional bandwidth, radiation efficiency, and radiation pattern are analyzed. Then, the input impedance matching of this antenna with the OTL is considered. In this case the current, near field distribution, radiation pattern, and reflection coefficient are calculated for different geometrical parameters. The results show that the loop inserted in the circuit can increase the bandwidth up to 42% and decreases the reflection coefficient in the OTL to −25 dB.

scholarly journals Defect Width Assessment Based on the Near-Field Magnetic Flux Leakage Method

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5424
Author(s):  
Erlong Li ◽  
Yiming Chen ◽  
Xiaotian Chen ◽  
Jianbo Wu
Keyword(s):  
Magnetic Flux ◽  
Near Field ◽  
Experimental Studies ◽  
Magnetic Flux Leakage ◽  
Geometrical Parameters ◽  
Destructive Testing ◽  
Lift Off ◽  
Two Peaks ◽  
Non Destructive ◽  
Flux Leakage

Magnetic flux leakage (MFL) testing has been widely used as a non-destructive testing method for various materials. However, it is difficult to separate the influences of the defect geometrical parameters such as depth, width, and length on the received leakage signals. In this paper, a “near-field” MFL method is proposed to quantify defect widths. Both the finite element modelling (FEM) and experimental studies are carried out to investigate the performance of the proposed method. It is found that that the distance between two peaks of the “near-field” MFL is strongly related to the defect width and lift-off value, whereas it is slightly affected by the defect depth. Based on this phenomenon, a defect width assessment relying on the “near-field” MFL method is proposed. Results show that relative judging errors are less than 5%. In addition, the analytical expression of the “near-field” MFL is also developed.

scholarly journals Near-Field Resolution in Planar Source Reconstructions

2020 ◽  
Author(s):  
Maria Antonia Maisto ◽  
Rocco Pierri ◽  
Raffaele Solimene
Keyword(s):  
Near Field ◽  
Geometrical Parameters ◽  
Planar Surface ◽  
Magnetic Current ◽  
Spread Function ◽  
Planar Source ◽  
Inverse Source Problems ◽  
Spatially Varying ◽  
Resolution Estimation

<div>This paper deals with the classical question of estimating the achievable resolution in terms of the configuration parameters in inverse source problems. In particular, the study focuses on the case of a planar surface magnetic current which is to be reconstructed from near-field observed over a bounded rectangular aperture parallel to the source domain. Here, the plan is to work out a resolution estimation that precisely captures the spatially varying behaviour entailed by the near-field and aspect-limited configuration. To this end, the pertinent radiation operator is inverted by an adjoint inversion scheme (a backpropagation- like method) and the corresponding point-spread function is analytically estimated. Numerical examples show that the derived resolution estimation clearly points out the role of the geometrical parameters of the configuration and it is more accurate than other literature results.</div>

Calibration technique for scanning near-field optical microscopes for measuring the geometrical parameters of objects in the shear-force mode

2012 ◽  
Vol 55 (9) ◽  
pp. 984-989
Author(s):  
A. Yu. Kuzin ◽  
P. A. Todua ◽  
V. I. Panov ◽  
A. A. Ezhov ◽  
D. A. Muzychenko
Keyword(s):  
Shear Force ◽  
Near Field ◽  
Geometrical Parameters ◽  
Calibration Technique ◽  
Force Mode

scholarly journals Spectral Engineering Via Complex Patterns of Circular Nano-Object Miniarrays: II. Concave Patterns Tunable by Integrated Lithography Realized by Circularly Polarized Light

Plasmonics ◽  
2020 ◽  
Author(s):  
Emese Tóth ◽  
Áron Sipos ◽  
Olivér A. Fekete ◽  
Mária Csete
Keyword(s):  
Spectral Response ◽  
Near Field ◽  
Azimuthal Angle ◽  
Polarized Light ◽  
Geometrical Parameters ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Rectangular Pattern ◽  
Beam Incident ◽  
Potential Applications

AbstractThe use of circularly polarized beams in interferometric illumination of colloid sphere monolayers enables the direct fabrication of rectangular patterns composed of circular nanohole miniarrays in metal films. This paper presents a study on the spectral and near-field effects of complex rectangular patterns consisted of a central nanoring and slightly rotated satellite nanocrescents in azimuthal orientations, which promote coupling between localized and propagating plasmons. To inspect the localized modes separately, we investigate the spectral responses and near-field phenomena of hexagonal patterns composed of uniform nanorings and nanocrescents, which can be fabricated by a single, homogeneous, circularly polarized beam incident perpendicularly and obliquely, respectively. To understand the interaction of localized and propagating modes, we analyze artificial rectangular patterns composed of a singlet nanoring, a singlet horizontal nanocrescent, and a quadrumer of four slightly rotated nanocrescents. The results demonstrate that on the rectangular pattern of a singlet horizontal nanocrescent the interacting C2 and C1 localized resonances in the C orientation ($$0^{\circ }$$ 0 ∘ azimuthal angle) and the U localized resonance coupled with propagating surface plasmon polaritons (SPPs) in the U orientation ($$90^{\circ }$$ 90 ∘ azimuthal angle) manifest themselves in similar split spectra. Moreover, split spectra appear due to the coupling of the azimuthal orientation independent localized resonance on the nanorings and the SPPs propagating on their rectangular pattern in the U orientation. The spectral response of the complex miniarray pattern can be precisely tuned by varying the geometrical parameters of the moderately interacting nanoholes and the pattern period. In appropriate configurations, the fluorescence of the dipolar emitters is enhanced, which has potential applications in bio-object detection.

scholarly journals Near-Field Resolution in Planar Source Reconstructions

2020 ◽  
Author(s):  
Maria Antonia Maisto ◽  
Rocco Pierri ◽  
Raffaele Solimene
Keyword(s):  
Near Field ◽  
Geometrical Parameters ◽  
Planar Surface ◽  
Magnetic Current ◽  
Spread Function ◽  
Planar Source ◽  
Inverse Source Problems ◽  
Spatially Varying ◽  
Resolution Estimation

<div>This paper deals with the classical question of estimating the achievable resolution in terms of the configuration parameters in inverse source problems. In particular, the study focuses on the case of a planar surface magnetic current which is to be reconstructed from near-field observed over a bounded rectangular aperture parallel to the source domain. Here, the plan is to work out a resolution estimation that precisely captures the spatially varying behaviour entailed by the near-field and aspect-limited configuration. To this end, the pertinent radiation operator is inverted by an adjoint inversion scheme (a backpropagation- like method) and the corresponding point-spread function is analytically estimated. Numerical examples show that the derived resolution estimation clearly points out the role of the geometrical parameters of the configuration and it is more accurate than other literature results.</div>

Vortex formation of a finite-span synthetic jet: effect of rectangular orifice geometry

2014 ◽  
Vol 745 ◽  
pp. 180-207 ◽  
Author(s):  
Tyler Van Buren ◽  
Edward Whalen ◽  
Michael Amitay
Keyword(s):  
Aspect Ratio ◽  
Near Field ◽  
Vortex Formation ◽  
Synthetic Jet ◽  
Stereoscopic Particle Image Velocimetry ◽  
Flow Structures ◽  
Geometrical Parameters ◽  
Neck Length ◽  
Finite Span ◽  
Aspect Ratios

AbstractThe formation and evolution of flow structures of a finite-span synthetic jet issuing into a quiescent flow were investigated experimentally using stereoscopic particle image velocimetry (SPIV). The effect of two geometrical parameters, the orifice aspect ratio and the neck length, were explored at a Strouhal number of 0.115 and a Reynolds number of 615. Normalized orifice neck lengths of 2, 4 and 6 and aspect ratios of 6, 12, and 18 were examined. It was found that the effect of the aspect ratio is much larger than the effect of the neck length, and as the aspect ratio increases the size of the edge vortices decreases and the presence of secondary structures is more evident. Moreover, axis switching was observed and its streamwise location increases as the aspect ratio increases. The effect of the neck length on the flow structures and the evolution of the synthetic jet was found to be secondary, where the effect was only in the very near field (i.e. close to the jet’s orifice).

Sign in / Sign up

Export Citation Format

Share Document