scholarly journals Rapidly convergent quasi-periodic Green functions for scattering by arrays of cylinders—including Wood anomalies

2017 ◽  
Vol 473 (2199) ◽  
pp. 20160802 ◽  
Author(s):  
Oscar P. Bruno ◽  
Agustin G. Fernandez-Lado
Keyword(s):  
Green Function ◽  
Transverse Electric ◽  
Resonance Region ◽  
Transverse Magnetic ◽  
Electric Polarization ◽  
Arbitrary Cross Section ◽  
Full Spectrum ◽  
Recent Contribution ◽  
Periodic Arrays ◽  
Wood Anomaly

This paper presents a full-spectrum Green-function methodology (which is valid, in particular, at and around Wood-anomaly frequencies) for evaluation of scattering by periodic arrays of cylinders of arbitrary cross section—with application to wire gratings, particle arrays and reflectarrays and, indeed, general arrays of conducting or dielectric bounded obstacles under both transverse electric and transverse magnetic polarized illumination. The proposed method, which, for definiteness, is demonstrated here for arrays of perfectly conducting particles under transverse electric polarization, is based on the use of the shifted Green-function method introduced in a recent contribution (Bruno & Delourme 2014 J. Computat. Phys. 262 , 262–290 ( doi:10.1016/j.jcp.2013.12.047 )). A certain infinite term arises at Wood anomalies for the cylinder-array problems considered here that is not present in the previous rough-surface case. As shown in this paper, these infinite terms can be treated via an application of ideas related to the Woodbury–Sherman–Morrison formulae. The resulting approach, which is applicable to general arrays of obstacles even at and around Wood-anomaly frequencies, exhibits fast convergence and high accuracies. For example, a few hundreds of milliseconds suffice for the proposed approach to evaluate solutions throughout the resonance region (wavelengths comparable to the period and cylinder sizes) with full single-precision accuracy.

scholarly journals Perturbations of the scattering resonances of an open cavity by small particles: Part II—the transverse electric polarization case

2021 ◽  
Vol 72 (2) ◽  
Author(s):  
Habib Ammari ◽  
Alexander Dabrowski ◽  
Brian Fitzpatrick ◽  
Pierre Millien
Keyword(s):  
Small Volume ◽  
Transverse Electric ◽  
Order Term ◽  
Transverse Magnetic ◽  
Electric Polarization ◽  
Open Cavity ◽  
Small Particles ◽  
Cavity Modes ◽  
Transverse Magnetic Polarization ◽  
Scattering Resonances

AbstractThis paper is concerned with the scattering resonances of open cavities. It is a follow-up of Ammari et al. (ZAMP 71:102, 2020), where the transverse magnetic polarization was assumed. In that case, using the method of matched asymptotic expansions, the leading-order term in the shifts of scattering resonances due to the presence of small particles of arbitrary shapes was derived and the effect of radiation on the perturbations of open cavity modes was characterized. The derivations were formal. In this paper, we consider the transverse electric polarization and prove a small-volume formula for the shifts in the scattering resonances of a radiating dielectric cavity perturbed by small particles. We show a strong enhancement in the frequency shift in the case of subwavelength particles with dipole resonances. We also consider exceptional scattering resonances and perform small-volume asymptotic analysis near them. A significant observation is the large-amplitude splitting of exceptional scattering resonances induced by small particles. Our method in this paper relies on pole-pencil decompositions of volume integral operators.

Single-peak-regulation and wide-angle dual-band metamaterial absorber based on hollow-cross and solid-cross resonators

2020 ◽  
Vol 91 (3) ◽  
pp. 30901
Author(s):  
Yibo Tang ◽  
Longhui He ◽  
Jianming Xu ◽  
Hailang He ◽  
Yuhan Li ◽  
...  
Keyword(s):  
Transverse Electric ◽  
Surface Current ◽  
Dielectric Substrate ◽  
Transverse Magnetic ◽  
Metamaterial Absorber ◽  
Absorption Peak ◽  
Dual Band ◽  
Single Peak ◽  
Wide Angle ◽  
Surface Current Density

A dual-band microwave metamaterial absorber with single-peak regulation and wide-angle absorption has been proposed and illustrated. The designed metamaterial absorber is consisted of hollow-cross resonators, solid-cross resonators, dielectric substrate and metallic background plane. Strong absorption peak coefficients of 99.92% and 99.55% are achieved at 8.42 and 11.31 GHz, respectively, which is basically consistent with the experimental results. Surface current density and changing material properties are employed to illustrate the absorptive mechanism. More importantly, the proposed dual-band metamaterial absorber has the adjustable property of single absorption peak and could operate well at wide incidence angles for both transverse electric (TE) and transverse magnetic (TM) waves. Research results could provide and enrich instructive guidances for realizing a single-peak-regulation and wide-angle dual-band metamaterial absorber.

Magnetic plasmons induced in a dielectric-metal heterostructure by optical magnetism

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Shulei Li ◽  
Lidan Zhou ◽  
Mingcheng Panmai ◽  
Jin Xiang ◽  
Sheng Lan
Keyword(s):  
Transverse Electric ◽  
Incidence Angle ◽  
High Sensitivity ◽  
Critical Value ◽  
Transverse Magnetic ◽  
Quality Factors ◽  
Light Spectrum ◽  
Optical Resonances ◽  
Scattering Spectra ◽  
Plasmon Polaritons

Abstract We investigate numerically and experimentally the optical properties of the transverse electric (TE) waves supported by a dielectric-metal heterostructure. They are considered as the counterparts of the surface plasmon polaritons (i.e., the transverse magnetic (TM) waves) which have been extensively studied in the last several decades. We show that TE waves with resonant wavelengths in the visible light spectrum can be excited in a dielectric-metal heterostructure when the optical thickness of the dielectric layer exceeds a critical value. We reveal that the electric and magnetic field distributions for the TE waves are spatially separated, leading to higher quality factors or narrow linewidths as compared with the TM waves. We calculate the thickness, refractive index and incidence angle dispersion relations for the TE waves supported by a dielectric-metal heterostructure. In experiments, we observe optical resonances with linewidths as narrow as ∼10 nm in the reflection or scattering spectra of the TE waves excited in a Si3N4/Ag heterostructure. Finally, we demonstrate the applications of the lowest-order TE wave excited in a Si3N4/Ag heterostructure in optical display with good chromaticity and optical sensing with high sensitivity.

Sensitivity characterization of polarization operating by embedded reflective grating

2021 ◽  
Author(s):  
Jiaman Hong ◽  
Bo Wang ◽  
Xiaoqing Zhu ◽  
Zhichao Xiong ◽  
Yusen Huang ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Electric Field Intensity ◽  
High Efficiency ◽  
Transverse Electric ◽  
Tolerance Analysis ◽  
Transverse Magnetic ◽  
Infrared Band ◽  
Element Analysis ◽  
Field Intensity Distribution

In this paper, a novel embedded reflective grating (ERG) is presented to realize bi-function polarization operating at infrared band by finite element analysis (FEM). For transverse electric (TE) polarization, a two-port output (0th and −2nd orders) with an efficiency of more than 47% and excellent uniformity can be obtained. For transverse magnetic (TM) polarization, a high efficiency output of 94.72% can be achieved at the −2th order. The results of the analysis of the electric field intensity distribution, angular and wavelength bandwidths further demonstrate the advantages of the proposed grating. In addition, the tolerance analysis of period and duty cycle prove the feasibility of the grating in practical production.

scholarly journals Quad-Band Plasmonic Perfect Absorber for Visible Light with a Patchwork of Silicon Nanorod Resonators

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1954 ◽  
Author(s):  
Can Cao ◽  
Yongzhi Cheng
Keyword(s):  
Visible Light ◽  
Transverse Electric ◽  
Transverse Magnetic ◽  
Localized Surface Plasmon ◽  
Perfect Absorber ◽  
Absorption Properties ◽  
Perfect Absorption ◽  
Potential Applications ◽  
Polarization Insensitive ◽  
Band Absorption

In this paper, a plasmonic perfect absorber (PPA) based on a silicon nanorod resonator (SNRR) for visible light is proposed and investigated numerically. The proposed PPA is only a two-layer nanostructure consisting of a SNRR periodic array and metal substrate. The perfect absorption mainly originates from excitation of the localized surface plasmon resonance (LSPR) mode in the SNRR structure. The absorption properties of this design can be adjusted by varying the radius (r) and height (h) of the SNRR structure. What is more, the stronger quad-band absorption can be achieved by combing four different radius of the SNRR in one period as a super unit-cell. Numerical simulation indicates that the designed quad-band PPA can achieve the absorbance of 99.99%, 99.8%, 99.8%, and 92.2% at 433.5 THz, 456 THz, 482 THz, and 504.5 THz, respectively. Further simulations show that the proposed PPA is polarization-insensitive for both transverse electric (TE) and transverse magnetic (TM) modes. The proposed PPA can be a desirable candidate for some potential applications in detecting, sensing, and visible spectroscopy.

Bandwidth Control of Loop Type Frequency Selective Surfaces Using Dual Elements in Various Arrangements

2021 ◽  
Author(s):  
Nickolas Littman ◽  
Steven G. O'Keefe ◽  
Amir Galehdar ◽  
Hugo G. Espinosa ◽  
David V. Thiel
Keyword(s):  
Stop Band ◽  
Transverse Magnetic ◽  
Electric Polarization ◽  
Capacitive Coupling ◽  
Electromagnetic Properties ◽  
Frequency Selective Surfaces ◽  
Simple Loop ◽  
Bandwidth Control ◽  
Frequency Selective ◽  
The Individual

Abstract Frequency-selective surfaces (FSSs) have applications across multiple disciplines due to their unique electromagnetic properties. This paper investigates the use of both rounded square loops (RSLs), and simple loop type dual elements arranged in unique patterns, to control the transmission and reflection bandwidth and resonant frequencies over KU and K frequency bands supported by equivalent circuit models (ECMs). The FSSs were fabricated using laser engraving to create conductive loop type elements on a thin, flexible and optically transparent Mylar substrate (relative permittivity of 2.7 and thickness of 65m). The frequency response of the surfaces are controlled through the element self-inductance and capacitive coupling with neighbouring elements. This work shows that different arrangements result in the formation of multiple distinct resonances. The theoretical and experimental results were in good agreement where rounded squares and dual element arrays were employed to create broadband and multiband band-stop FSSs. A polarization sensitive surface exhibited stop-bands at 12GHz and 16GHz in transverse electric polarization and a stop-band at 14.4GHz in transverse magnetic polarization. This technique can be applied to any periodic array through careful selection of the individual elements in the array, as well as their arrangement.

scholarly journals Silicon Waveguide Optical Isolator with Directly Bonded Magneto-Optical Garnet

2019 ◽  
Vol 9 (3) ◽  
pp. 609 ◽  
Author(s):  
Yuya Shoji ◽  
Tetsuya Mizumoto
Keyword(s):  
Phase Shift ◽  
Transverse Electric ◽  
Core Layer ◽  
Transverse Magnetic ◽  
Silicon Waveguide ◽  
Optical Isolation ◽  
Tm Mode ◽  
Mode Converters ◽  
Optical Isolators ◽  
Thin Interlayer

Silicon waveguide optical isolators were fabricated by direct bonding of magneto-optical (MO) garnet. The technique allowed efficient MO phase shift owing to the use of single-crystalline garnet and negligibly thin interlayer on the silicon core layer. A Mach–Zehnder interferometer (MZI) provided optical isolation utilizing the MO phase shift. High isolation, wide bandwidth, and temperature-insensitive operations had been demonstrated by tailoring the MZI design. Also, transverse electric (TE)–transverse magnetic (TM) mode converters were integrated to control operating polarization. In this paper, we reviewed these progresses on silicon waveguide optical isolators.

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