scholarly journals Near-Field Excitation of Bound States in the Continuum in All-Dielectric Metasurfaces through a Coupled Electric/Magnetic Dipole Model

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 998
Author(s):  
Diego R. Abujetas ◽  
José A. Sánchez-Gil
Keyword(s):  
Magnetic Dipole ◽  
Density Of States ◽  
Bound States ◽  
Local Density ◽  
Near Field ◽  
Field Pattern ◽  
Local Density Of States ◽  
Optical Modes ◽  
Source Excitation ◽  
The Continuum

Resonant optical modes arising in all-dielectric metasurfaces have attracted much attention in recent years, especially when so-called bound states in the continuum (BICs) with diverging lifetimes are supported. With the aim of studying theoretically the emergence of BICs, we extend a coupled electric and magnetic dipole analytical formulation to deal with the proper metasurface Green function for the infinite lattice. Thereby, we show how to excite metasurface BICs, being able to address their near-field pattern through point-source excitation and their local density of states. We apply this formulation to fully characterize symmetry-protected BICs arising in all-dielectric metasurfaces made of Si nanospheres, revealing their near-field pattern and local density of states, and, thus, the mechanisms precluding their radiation into the continuum. This formulation provides, in turn, an insightful and fast tool to characterize BICs (and any other leaky/guided mode) near fields in all-dielectric (and also plasmonic) metasurfaces, which might be especially useful for the design of planar nanophotonic devices based on such resonant modes.

scholarly journals Mapping the Radiative and the Apparent Nonradiative Local Density of States in the Near Field of a Metallic Nanoantenna

ACS Photonics ◽  
2015 ◽  
Vol 2 (2) ◽  
pp. 189-193 ◽  
Author(s):  
Da Cao ◽  
Alexandre Cazé ◽  
Michele Calabrese ◽  
Romain Pierrat ◽  
Nathalie Bardou ◽  
...  
Keyword(s):  
Density Of States ◽  
Local Density ◽  
Near Field ◽  
Local Density Of States

scholarly journals Distance dependence of the local density of states in the near field of a disordered plasmonic film

2012 ◽  
Vol 37 (14) ◽  
pp. 3006 ◽  
Author(s):  
E. Castanié ◽  
V. Krachmalnicoff ◽  
A. Cazé ◽  
R. Pierrat ◽  
Y. De Wilde ◽  
...  
Keyword(s):  
Density Of States ◽  
Local Density ◽  
Near Field ◽  
Local Density Of States ◽  
Distance Dependence

scholarly journals Study on Green’s function on topological insulator surface

2018 ◽  
Vol 376 (2125) ◽  
pp. 20150246 ◽  
Author(s):  
Bo Lu ◽  
Yukio Tanaka
Keyword(s):  
Green’S Function ◽  
Density Of States ◽  
Green's Function ◽  
Topological Insulator ◽  
Bound States ◽  
Local Density ◽  
Josephson Current ◽  
Majorana Fermion ◽  
Local Density Of States ◽  
Andreev Bound States

In the theory of superconducting junctions, Green’s function has an important role for obtaining Andreev bound states, local density of states and Josephson current in a systematic way. In this article, we show how to construct Green’s function on the surface of a topological insulator following McMillan’s formalism where the energy spectrum of electrons obeys a linear dispersion. For a model of a superconductor (S)/ferromagnet (F)/normal metal (N) junction, we show that the generation of a Majorana fermion gives rise to the enhanced local density of states and pair amplitude of odd-frequency pairing. We also derive an extended Furusaki–Tsukada’s formula of DC Josephson current in S/F/S junctions. The obtained Josephson current depends on the direction and magnitude of the magnetization. This article is part of the theme issue ‘Andreev bound states’.

Near-field Studies of Thermal Radiation and Local Density of States

2017 ◽  
Author(s):  
Y. De Wilde ◽  
F. Peragut ◽  
V. Krachmalnicoff ◽  
R. Pierrat ◽  
R. Carminati ◽  
...  
Keyword(s):  
Thermal Radiation ◽  
Density Of States ◽  
Local Density ◽  
Near Field ◽  
Field Studies ◽  
Local Density Of States

Aspects of a Single Vortex in d-Wave Superconductors

1998 ◽  
Vol 12 (10) ◽  
pp. 989-1005 ◽  
Author(s):  
Y. Morita ◽  
M. Kohmoto ◽  
K. Maki
Keyword(s):  
Density Of States ◽  
Bound States ◽  
Local Density ◽  
Quantum Limit ◽  
Vortex Center ◽  
Local Density Of States ◽  
S Wave ◽  
Single Vortex ◽  
Quasiparticle Spectrum ◽  
D Wave

Physical properties of a single vortex in d-wave superconductors are studied theoretically. After a brief review on a single vortex in "conventional" s-wave superconductors and the d-wave superconductivity underlying the hole-doped high-T c cuprates, we go on to study the quasiparticle spectrum around a single vortex in the high-T c superconductors. One of the characteristics of the high-T c superconductors is that they are close to the "quantum limit" (pFξ ~ O(1)). A new picture emerges of the quasiparticle spectrum. Instead of thousands of bound states in a "conventional" s-wave superconductor, we find only a few peaks in the local density of states at the vortex center. Further there are low-lying excitations stretched in four diagonal directions and they have no counterpart in s-wave superconductors.

scholarly journals Supersymmetric Cluster Expansions and Applications to Random Schrödinger Operators

2021 ◽  
Vol 24 (1) ◽  
Author(s):  
Luca Fresta
Keyword(s):  
Density Of States ◽  
Local Density ◽  
Schrödinger Operators ◽  
Random Schrödinger Operators ◽  
Schrodinger Operators ◽  
Local Density Of States ◽  
Weak Disorder ◽  
Cluster Expansions ◽  
Strong Disorder ◽  
Lifshitz Tail

AbstractWe study discrete random Schrödinger operators via the supersymmetric formalism. We develop a cluster expansion that converges at both strong and weak disorder. We prove the exponential decay of the disorder-averaged Green’s function and the smoothness of the local density of states either at weak disorder and at energies in proximity of the unperturbed spectrum or at strong disorder and at any energy. As an application, we establish Lifshitz-tail-type estimates for the local density of states and thus localization at weak disorder.

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