scholarly journals Fano resonance in metallic grating via strongly coupled subwavelength resonators

2020 ◽  
pp. 1-25
Author(s):  
JUNSHAN LIN ◽  
HAI ZHANG
Keyword(s):  
Imaginary Part ◽  
Fano Resonance ◽  
Scattering Problem ◽  
Resonant Scattering ◽  
Coupled Resonators ◽  
Incident Wavelength ◽  
Strongly Coupled ◽  
Metallic Grating ◽  
Radiation Induced ◽  
Resonant Radiation

We investigate the Fano resonance in grating structures using coupled resonators. The grating consists of a perfectly conducting slab with periodically arranged subwavelength slit holes, where inside each period, a pair of slits sit very close to each other. The slit holes act as resonators and are strongly coupled. It is shown rigorously that there exist two groups of resonances corresponding to poles of the scattering problem. One sequence of resonances has imaginary part in the order of ε, where ε is the size of the slit aperture, while the other sequence has imaginary part in the order of ε2. When coupled with the incident wave at resonant frequencies, the narrow-band resonant scattering induced by the latter will interfere with the broader background resonant radiation induced by the former. The interference of these two resonances generates the Fano-type transmission anomaly, which persists in the whole radiation continuum of the grating structure as long as the slit aperture size is small compared to the incident wavelength.

scholarly journals Transmission Properties of Metallic Grating with Subwavelength Slits in THz Frequency Region

2007 ◽  
Vol 2007 ◽  
pp. 1-4 ◽  
Author(s):  
Dong Liang ◽  
Qirong Xing ◽  
Zhen Tian ◽  
Changlei Wang ◽  
Weili Zhang ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Wavelength Region ◽  
Grating Period ◽  
Frequency Region ◽  
Incident Wavelength ◽  
Long Wavelength ◽  
Metallic Grating ◽  
Transmission Properties ◽  
And Control ◽  
Good Agreement

This paper presents a fully experimental and theoretical study on transmission properties of a deep metallic grating with subwavelength slits in THz frequency region by using THz time domain spectroscopy (THz-TDS). The grating exposed top-polarized incident wave exhibits enhanced nonresonant transmission in the long-wavelength region where the incident wavelength is larger than the grating period. Wood anomalies are observed when the wavelength is comparable to the grating period. Strict theory is given to explain the experimental results and the two are in good agreement. It is proposed that the Wood dips may be considered a criterion and a tool to judge and control the uniformity or fabricating accuracy of the grating period.

scholarly journals Key Role of Cytochrome C for Apoptosis Detection Using Raman Microimaging in an Animal Model of Brain Ischemia with Insulin Treatment

2019 ◽  
Vol 73 (10) ◽  
pp. 1208-1217 ◽  
Author(s):  
Vanessa Russo ◽  
Patrizio Candeloro ◽  
Natalia Malara ◽  
Gerardo Perozziello ◽  
Michelangelo Iannone ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Brain Ischemia ◽  
Hippocampal Neurons ◽  
Apoptotic Cell ◽  
Resonant Scattering ◽  
Global Ischemia ◽  
Alternative Mechanism ◽  
Mongolian Gerbils ◽  
Incident Wavelength

Brain ischemia represents a leading cause of death and disability in industrialized countries. To date, therapeutic intervention is largely unsatisfactory and novel strategies are required for getting better protection of neurons injured by cerebral blood flow restriction. Recent evidence suggests that brain insulin leads to protection of neuronal population undergoing apoptotic cell death via modulation of oxidative stress and mitochondrial cytochrome c (CytC), an effect to be better clarified. In this work, we investigate on the effect of insulin given intracerebroventricular (ICV) before inducing a transient global ischemia by bilateral occlusion of the common carotid arteries (BCCO) in Mongolian gerbils (MG). The transient (3 min) global ischemia in MG is observed to produce neurodegenerative effect mainly into CA3 hippocampal region, 72 h after cerebral blood restriction. Intracerebroventricular microinfusion of insulin significantly prevents the apoptosis of CA3 hippocampal neurons. Histological observation, after hematoxylin and eosin staining, puts in evidence the neuroprotective role of insulin, but Raman microimaging provides a clearer insight in the CytC mechanism underlying the apoptotic process. Above all, CytC has been revealed to be an outstanding, innate Raman marker for monitoring the cells status, thanks to its resonant scattering at 530 nm of incident wavelength and to its crucial role in the early stages of cells apoptosis. These data support the hypothesis of an insulin-dependent neuroprotection and antiapoptotic mechanism occurring in the brain of MG undergoing transient brain ischemia. The observed effects occurred without any peripheral change on serum glucose levels, suggesting an alternative mechanism of insulin-induced neuroprotection.

High Polaried Transmission Effects for Double-Layer Metallic Grating Films on GaN Substrate

2011 ◽  
Vol 295-297 ◽  
pp. 1289-1293
Author(s):  
Bing Cao ◽  
Gui Ju Zhang ◽  
Qin Han ◽  
Chin Hua Wang ◽  
Jian Feng Wang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Double Layer ◽  
Transition Layer ◽  
Light Transmission ◽  
Light Emitting Diode ◽  
Extinction Ratio ◽  
Polarized Light ◽  
Incident Wavelength ◽  
Metallic Grating ◽  
Low Refractive Index

Highly polarized light transmission from GaN based light emitting diode is proposed using a double-layer metallic grating film and a dielectric transition layer. TM mode transmission and the polarized extinction ratio (ER) are calculated using commercial software, based on a full vector implementation of Rigorous Coupled Wave Analysis (RCWA) algorithm. Such a thin-film double-layer grating with subwavelength metallic stripes are designed and simulated by perfect parameters of period, thickness and filling factor for achieving good polarization properties. It is found that TM transmission and ER are almost stable and flat under different slit arrays of the double-layer grating. The polarized structure shows larger width of incident wavelength with a transition layer of a low refractive index than that of a high refractive index, but higher TM transmission and ER can be obtained for low refractive index transition layer. Flat sensitivity and high transmission of the TM mode on the double-layer metal grating thickness have been achieved. Up to 100nm range of the grating height can be employed to achieve TM transmission more than 92% while ER> 20dB. The results provide guidance in designing, optimizing and fabricating the integrated GaN-based and polarized photonic devices.

scholarly journals The imaginary part of the static potential in strongly coupled anisotropic plasma

2013 ◽  
Vol 2013 (11) ◽  
Author(s):  
Kazem Bitaghsir Fadafan ◽  
Dimitrios Giataganas ◽  
Hesam Soltanpanahi
Keyword(s):  
Imaginary Part ◽  
Anisotropic Plasma ◽  
Static Potential ◽  
Strongly Coupled

scholarly journals Relaxation- and decoherence-free subspaces in networks of weakly and strongly coupled resonators

2007 ◽  
Vol 322 (9) ◽  
pp. 2077-2084 ◽  
Author(s):  
M.A. de Ponte ◽  
S.S. Mizrahi ◽  
M.H.Y. Moussa
Keyword(s):  
Coupled Resonators ◽  
Strongly Coupled ◽  
Decoherence Free Subspaces

Linear and Nonlinear Wave Models Based on Hamilton’s Principle and Stream-Function Theory: CMSE and IGN

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
J. W. Kim ◽  
R. C. Ertekin ◽  
K. J. Bai
Keyword(s):  
Stream Function ◽  
Gravity Waves ◽  
Function Theory ◽  
Scattering Problem ◽  
Resonant Scattering ◽  
Hamilton’S Principle ◽  
Bragg Scattering ◽  
Hamilton's Principle ◽  
Numerical Predictions ◽  
Wave Models

Recently, two wave models based on the stream-function theory have been derived from Hamilton’s principle for gravity waves. One is the irrotational Green–Naghdi (IGN) equation and the other is the complementary mild-slope equation (CMSE). The IGN equation has been derived to describe refraction and diffraction of nonlinear gravity waves in the time domain and in water of finite but arbitrary bathymetry. The CMSE has been derived to consider the same problem in the (linear) frequency domain. In this paper, we first discuss the two models from the viewpoint of Hamilton’s principle. Then the two models are applied to a resonant scattering of Stokes waves over periodic undulations, or the Bragg scattering problem. The numerical results are compared with existing numerical predictions and experimental data. It is found here that Level 3 IGN equation can describe Bragg scattering well for arbitrary bathymetry.

Design of In-Line Filters With Transmission Zeros Using Strongly Coupled Resonators Pairs

2018 ◽  
Vol 66 (8) ◽  
pp. 3836-3846 ◽  
Author(s):  
Giuseppe Macchiarella ◽  
Simone Bastioli ◽  
Richard V. Snyder
Keyword(s):  
Coupled Resonators ◽  
Strongly Coupled ◽  
Transmission Zeros

Near-field Imaging Point-like Scatterers and Extended Elastic Solid in a Fluid

2016 ◽  
Vol 19 (5) ◽  
pp. 1317-1342
Author(s):  
Tao Yin ◽  
Guanghui Hu ◽  
Liwei Xu
Keyword(s):  
Near Field ◽  
Scattering Problem ◽  
Acoustic Scattering ◽  
Elastic Solid ◽  
Field Measurements ◽  
Factorization Method ◽  
Music Algorithm ◽  
Incident Wavelength ◽  
Imaging Point ◽  
Necessary And Sufficient

AbstractConsider the time-harmonic acoustic scattering from an extended elastic body surrounded by a finite number of point-like obstacles in a fluid. We assume point source waves are emitted from arrayed transducers and the signals of scattered near-field data are recorded by receivers not far away from the scatterers (compared to the incident wavelength). The forward scattering can be modeled as an interaction problem between acoustic and elastic waves together with a multiple scattering problem between the extend solid and point scatterers. We prove a necessary and sufficient condition that can be used simultaneously to recover the shape of the extended elastic solid and to locate the positions of point scatterers. The essential ingredient in our analysis is the outgoing-to-incoming (OtI) operator applied to the resulting near-field response matrix (or operator). In the first part, we justify the MUSIC algorithm for locating point scatterers from near-field measurements. In the second part, we apply the factorization method, the continuous analogue of MUSIC, to the two-scale scattering problem for determining both extended and point scatterers. Numerical examples in 2D are demonstrated to show the validity and accuracy of our inversion algorithms.

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