scholarly journals Scattering Properties of PT-Symmetric Chiral Metamaterials

Photonics ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 43
Author(s):  
Ioannis Katsantonis ◽  
Sotiris Droulias ◽  
Costas M. Soukoulis ◽  
Eleftherios N. Economou ◽  
Maria Kafesaki
Keyword(s):  
Pt Symmetry ◽  
Optical Systems ◽  
Symmetric System ◽  
Angle Of Incidence ◽  
Asymmetric Transmission ◽  
Chiral Metamaterials ◽  
Polarization Control ◽  
Gain Loss ◽  
Incident Waves ◽  
At Will

The combination of gain and loss in optical systems that respect parity–time (PT)-symmetry has pointed recently to a variety of novel optical phenomena and possibilities. Many of them can be realized by combining the PT-symmetry concepts with metamaterials. Here we investigate the case of chiral metamaterials, showing that combination of chiral metamaterials with PT-symmetric gain–loss enables a very rich variety of phenomena and functionalities. Examining a simple one-dimensional chiral PT-symmetric system, we show that, with normally incident waves, the PT-symmetric and the chirality-related characteristics can be tuned independently and superimposed almost at will. On the other hand, under oblique incidence, chirality affects all the PT-related characteristics, leading also to novel and uncommon wave propagation features, such as asymmetric transmission and asymmetric optical activity and ellipticity. All these features are highly controllable both by chirality and by the angle of incidence, making PT-symmetric chiral metamaterials valuable in a large range of polarization-control-targeting applications.

scholarly journals Connecting active and passive PT -symmetric Floquet modulation models

2020 ◽  
Author(s):  
Andrew K Harter ◽  
Yogesh N Joglekar
Keyword(s):  
Open Systems ◽  
Symmetric Case ◽  
Pt Symmetry ◽  
Time Dependent ◽  
Symmetric System ◽  
Complex Conjugate ◽  
Static Case ◽  
The Past ◽  
Gain Loss ◽  
Symmetric Phase

Abstract Open systems with gain, loss, or both, described by non-Hermitian Hamiltonians, have been a research frontier for the past decade. In particular, such Hamiltonians which possess parity-time (PT) symmetry feature dynamically stable regimes of unbroken symmetry with completely real eigenspectra that are rendered into complex conjugate pairs as the strength of the non-Hermiticity increases. By subjecting a PT-symmetric system to a periodic (Floquet) driving, the regime of dynamical stability can be dramatically affected, leading to a frequency-dependent threshold for the PT-symmetry breaking transition. We present a simple model of a time-dependent PT-symmetric Hamiltonian which smoothly connects the static case, a PT-symmetric Floquet case, and a neutral-PT-symmetric case. We analytically and numerically analyze the PT phase diagrams in each case, and show that slivers of PT-broken (PT-symmetric) phase extend deep into the nominally low (high) non-Hermiticity region.

Polarization control in two-pass anisotropic optical systems with a new Faraday mirror

1999 ◽  
Author(s):  
Mikhail A. Novikov ◽  
V. V. Ivanov ◽  
Valentin M. Gelikonov ◽  
Grigory V. Gelikonov
Keyword(s):  
Optical Systems ◽  
Polarization Control

scholarly journals Effect of Dissipation Factor on Reflected and Transmitted Powers of a Structure Containing Left-Handed Material Waveguide

2013 ◽  
Vol 8 ◽  
pp. 1-11
Author(s):  
Muin F. Ubeid ◽  
Mohammed M. Shabat ◽  
Mohammed O. Sid-Ahmed
Keyword(s):  
Boundary Conditions ◽  
Frequency Dependence ◽  
Dissipation Factor ◽  
Waveguide Structure ◽  
Angle Of Incidence ◽  
Conservation Of Energy ◽  
Left Handed ◽  
Electric And Magnetic Fields ◽  
Permittivity And Permeability ◽  
Incident Waves

In this paper a waveguide structure consisting of a pair of left-handed material (LHM) and dielectric slabs inserted in vacuum is investigated theoretically. Two cases of the LHM are considered, loss-less case and loss case as well as the frequency dependence of permittivity and permeability of it is taken into account. Maxwell's equations are used to determine the electric and magnetic fields of the incident waves at each layer. Snell's law is applied and the boundary conditions are imposed at each layer interface to calculate the reflected, transmitted and loss powers of the structure. Numerical results are illustrated to show the effect of frequency, angle of incidence and LHM thickness on the mentioned powers when the dissipation factor changes. The obtained results are in agreement with the law of conservation of energy.

scholarly journals High-Performance Asymmetric Optical Transmission Based on a Dielectric–Metal Metasurface

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2410
Author(s):  
Wenbing Liu ◽  
Lirong Huang ◽  
Jifei Ding ◽  
Chenkai Xie ◽  
Yi Luo ◽  
...  
Keyword(s):  
High Performance ◽  
Optical Transmission ◽  
Near Infrared ◽  
Contrast Ratio ◽  
Polarized Light ◽  
Infrared Region ◽  
Optical Systems ◽  
Asymmetric Transmission ◽  
Linearly Polarized ◽  
Transmittance Peak

Asymmetric optical transmission plays a key role in many optical systems. In this work, we propose and numerically demonstrate a dielectric–metal metasurface that can achieve high-performance asymmetric transmission for linearly polarized light in the near-infrared region. Most notably, it supports a forward transmittance peak (with a transmittance of 0.70) and a backward transmittance dip (with a transmittance of 0.07) at the same wavelength of 922 nm, which significantly enhances operation bandwidth and the contrast ratio between forward and backward transmittances. Mechanism analyses reveal that the forward transmittance peak is caused by the unidirectional excitation of surface plasmon polaritons and the first Kerker condition, whereas the backward transmittance dip is due to reflection from the metal film and a strong toroidal dipole response. Our work provides an alternative and simple way to obtain high-performance asymmetric transmission devices.

Black-and-White and Color Image-Tone Enhancement in Scanning Electron Microscopy

1969 ◽  
Vol 27 ◽  
pp. 86-87 ◽  
Author(s):  
Franco Rossi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Secondary Electron ◽  
Color Image ◽  
Optical Systems ◽  
Angle Of Incidence ◽  
Secondary Electron Yield ◽  
Writing Beam ◽  
Electron Yield ◽  
Scanning Electron

In scanning electron microscopy, the specimen surface is scanned with a very fine electron beam, and the emitted secondary electrons are used to control the intensity of a synchronized writing beam scanning the screen of a viewing tube. The resulting image is recorded photographically by using conventional optical systems. The brightness of the image elements depends on their secondary electron yield and the amplification factor. The secondary electron yield itself depends on the surface material, the angle of incidence, and the velocity of the primary beam.

scholarly journals Quantum simulation of PT-arbitrary-phase-symmetric systems

2021 ◽  
Author(s):  
Chao Zheng
Keyword(s):  
Quantum Simulation ◽  
Two Dimensions ◽  
Pt Symmetry ◽  
Dissipative Systems ◽  
Symmetric System ◽  
Experimental Investigations ◽  
Small Quantum ◽  
Arbitrary Phase ◽  
Complex Extension ◽  
Symmetric Systems

Abstract Parity-time-reversal (PT) symmetric quantum mechanics promotes the increasing research interest of non-Hermitian (NH) systems for the theoretical value, novel properties, and links to open and dissipative systems in various areas. Recently, anti-PT-symmetric systems and its featured properties start to be investigated. In this work, we develop the PT- and anti-PT symmetry to PT-arbitrary-phase symmetry (or PT-φ symmetry) for the first time, being analogous to bosons, fermions and anyons. It can also be seen as a complex extension of the PT-symmetry, unifying the PT and anti-PT symmetries and having properties intermediate between them. Many of the established concepts and mathematics in the PT-symmetric system are still compatible. We mainly investigate quantum simulation of this novel NH-system of two-dimensions in detail and discuss for higher-dimensional cases in general using the linear combinations of unitaries in the scheme of duality quantum computing, enabling implementations and experimental investigations of novel properties on both small quantum devices and near-term quantum computers.

scholarly journals Laboratory and numerical experiments on stem waves due to monochromatic waves along a vertical wall

2018 ◽  
Vol 25 (3) ◽  
pp. 521-535
Author(s):  
Sung Bum Yoon ◽  
Jong-In Lee ◽  
Young-Take Kim ◽  
Choong Hun Shin
Keyword(s):  
Small Amplitude ◽  
Numerical Experiments ◽  
Vertical Wall ◽  
Wave Pattern ◽  
Angle Of Incidence ◽  
Stokes Waves ◽  
Wave Heights ◽  
Incident Waves ◽  
Good Agreement ◽  
Monochromatic Waves

Abstract. In this study, both laboratory and numerical experiments are conducted to investigate stem waves propagating along a vertical wall developed by the incidence of monochromatic waves. The results show the following features: for small-amplitude waves, the wave heights along the wall show a slowly varying undulation. Normalized wave heights perpendicular to the wall show a standing wave pattern. The overall wave pattern in the case of small-amplitude waves shows a typical diffraction pattern around a semi-infinite thin breakwater. As the amplitude of incident waves increases, both the undulation intensity and the asymptotic normalized wave height decrease along the wall. For larger-amplitude waves with smaller angle of incidence, the measured data clearly show stem waves. Numerical simulation results are in good agreement with the results of laboratory experiments. The results of present experiments favorably support the existence and the properties of stem waves found by other researchers using numerical simulations. The characteristics of the stem waves generated by the incidence of monochromatic Stokes waves are compared with those of the Mach stem of solitary waves.

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