scholarly journals Band Gaps and Wavefunctions of Electrons Coupled to Pseudo Electromagnetic Waves in Rippled Graphene

2018 ◽  
Vol 12 (9) ◽  
pp. 1800072 ◽  
Author(s):  
Ramon Carrillo-Bastos ◽  
Gerardo G. Naumis
Keyword(s):  
Electromagnetic Waves ◽  
Band Gaps

Reflection of Electromagnetic Waves from Multiferroic TbMnO3

2012 ◽  
Vol 77 ◽  
pp. 225-230
Author(s):  
Igor V. Bychkov ◽  
Dmitry A. Kuzmin ◽  
Sergei J. Lamekhov ◽  
Leonid N. Butko ◽  
Vladimir G. Shavrov
Keyword(s):  
Reflection Coefficient ◽  
Electromagnetic Waves ◽  
Band Gaps ◽  
Electromagnetic Interactions ◽  
Coefficient Of Reflection

Reflection coefficient of electromagnetic waves from TbMnO3 surface with sinusoidal structure and permittivity are examined. Model of material with spin, elastic and electromagnetic interactions used. Resonance kind of reflection coefficient and of permittivity was shown. Found spectrum and reasoned existing of band-gaps in coefficient of reflection.

PHOTONIC GAPS IN PERIODIC DIELECTRIC STRUCTURES

1992 ◽  
Vol 06 (03) ◽  
pp. 139-144 ◽  
Author(s):  
C.T. CHAN ◽  
K.M. HO ◽  
C.M. SOUKOULIS
Keyword(s):  
Plane Wave ◽  
Electromagnetic Waves ◽  
Expansion Method ◽  
Dielectric Materials ◽  
Band Gaps ◽  
Plane Wave Expansion ◽  
Photonic Band Gaps ◽  
Plane Wave Expansion Method ◽  
Dielectric Structures ◽  
Photonic Band

Using a plane wave expansion method, we solved the Maxwell’s equations for the propagation of electromagnetic waves inside periodic dielectric materials, and found the existence of photonic band gaps in several classes of periodic dielectric structures.

Parametric oscillation of electromagnetic waves in momentum band gaps of a spatiotemporal crystal

2020 ◽  
Author(s):  
Seo-Joo Lee ◽  
Jagang Park ◽  
Hyukjoon Cho ◽  
Bumki Min ◽  
Yifan Wang ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Band Gaps ◽  
Parametric Oscillation

scholarly journals On the spectrum of waveguides in planar photonic bandgap structures

2015 ◽  
Vol 471 (2176) ◽  
pp. 20140673 ◽  
Author(s):  
B. M. Brown ◽  
V. Hoang ◽  
M. Plum ◽  
I. Wood
Keyword(s):  
Spectral Problem ◽  
Electromagnetic Waves ◽  
Axial Direction ◽  
Band Gaps ◽  
Photonic Crystal Waveguides ◽  
Linear Defect ◽  
Small Perturbations ◽  
Mode Spectrum ◽  
Guided Mode ◽  
Photonic Bandgap Structures

We study a Helmholtz-type spectral problem related to the propagation of electromagnetic waves in photonic crystal waveguides. The waveguide is created by introducing a linear defect into a two-dimensional periodic medium; the defect is infinitely extended and aligned with one of the coordinate axes. This perturbation introduces guided mode spectrum inside the band gaps of the fully periodic, unperturbed spectral problem. In the first part of the paper, we prove that guided mode spectrum can be created by arbitrarily ‘small’ perturbations. Secondly, we show that, after performing a Floquet decomposition in the axial direction of the waveguide, for any fixed value of the quasi-momentum k x , the perturbation generates at most finitely many new eigenvalues inside the gap.

scholarly journals Designing a One-Dimensional Photonic Crystal via Thue-Morse Sequence Containing Two Types of Double Negative Metamaterial

2021 ◽  
Author(s):  
Ali Baseri ◽  
Alireza Keshavarz
Keyword(s):  
Photonic Crystal ◽  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Electromagnetic Waves ◽  
Incidence Angle ◽  
Band Gaps ◽  
Double Negative ◽  
One Dimensional ◽  
Periodic Arrangement

Abstract This study investigates the propagating of electromagnetic waves through a one-dimensional quasi-photonic crystal with the transfer matrix method. Our proposed structure consists of two types of double negative metamaterials, organized according to the Thue-Morse sequence law. The results show that changing the structure via quasi-periodic arrangements makes the outcome more varied than applying the absolute periodic arrangement. Given that, our desirable results of interest are more conveniently achieved. The structure completely stops-both s and p polarization at the lower frequencies, for all incidence angles. It also partially stops s and p polarization, at higher frequencies. Moreover, the achieved transmittance spectrum contains several omnidirectional band-gaps, which remain invariant with changes in the incidence angle. The oscillation of the transmittance values also becomes more intense at higher orders of the period number. This study could pave the way for optimizing of photonic crystal circuits, splitters, switches, etc.

Dual-band all-dielectric chiral photonic crystal

2021 ◽  
Author(s):  
Lianlian Du ◽  
Yahong Liu ◽  
Xin Zhou ◽  
Liyun Tao ◽  
Meize Li ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Communication Systems ◽  
Electromagnetic Waves ◽  
Band Gaps ◽  
Dual Band ◽  
Two Dimensional ◽  
Edge States ◽  
Frequency Range ◽  
Crystal Unit Cell ◽  
Inner Diameter

Abstract We present an all-dielectric chiral photonic crystal that guides the propagation of electromagnetic waves without backscattering for dual bands. The chiral photonic crystal unit cell is composed of four dielectric cylinders with increasing inner diameter clockwise or anticlockwise, which leads to chirality. It is demonstrated that the proposed chiral photonic crystal can generate dual band gaps in gigahertz frequency range and has two types of chiral edge states, which is similar to topologically protected edge states. Hence, the interface formed by the proposed two-dimensional (2D) chiral photonic crystal can guide the propagation of electromagnetic waves without backscattering, and this complete propagation is immune to defects (position disorder or frequency disorder). To illustrate the applicability of the findings in communication systems, we report a duplexer and a power divider based on the present all-dielectric chiral photonic crystal.

Seti Space Missions

1997 ◽  
Vol 161 ◽  
pp. 761-776 ◽  
Author(s):  
Claudio Maccone
Keyword(s):  
Electromagnetic Waves ◽  
Space Missions ◽  
Gravitational Lens ◽  
The Sun ◽  
Space Antenna ◽  
Focal Distance ◽  
Large Space ◽  
The Earth ◽  
Space Antennas ◽  
New Space

AbstractSETI from space is currently envisaged in three ways: i) by large space antennas orbiting the Earth that could be used for both VLBI and SETI (VSOP and RadioAstron missions), ii) by a radiotelescope inside the Saha far side Moon crater and an Earth-link antenna on the Mare Smythii near side plain. Such SETIMOON mission would require no astronaut work since a Tether, deployed in Moon orbit until the two antennas landed softly, would also be the cable connecting them. Alternatively, a data relay satellite orbiting the Earth-Moon Lagrangian pointL2would avoid the Earthlink antenna, iii) by a large space antenna put at the foci of the Sun gravitational lens: 1) for electromagnetic waves, the minimal focal distance is 550 Astronomical Units (AU) or 14 times beyond Pluto. One could use the huge radio magnifications of sources aligned to the Sun and spacecraft; 2) for gravitational waves and neutrinos, the focus lies between 22.45 and 29.59 AU (Uranus and Neptune orbits), with a flight time of less than 30 years. Two new space missions, of SETI interest if ET’s use neutrinos for communications, are proposed.

Microwaves: Application in Electron Microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 140-141
Author(s):  
Anthony S-Y Leong ◽  
David W Gove
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Chemical Reactions ◽  
Electromagnetic Waves ◽  
Tissue Fixation ◽  
Primary Method ◽  
Dipolar Molecules ◽  
Wide Range ◽  
Time Required ◽  
Cryostat Sections

Microwaves (MW) are electromagnetic waves which are commonly generated at a frequency of 2.45 GHz. When dipolar molecules such as water, the polar side chains of proteins and other molecules with an uneven distribution of electrical charge are exposed to such non-ionizing radiation, they oscillate through 180° at a rate of 2,450 million cycles/s. This rapid kinetic movement results in accelerated chemical reactions and produces instantaneous heat. MWs have recently been applied to a wide range of procedures for light microscopy. MWs generated by domestic ovens have been used as a primary method of tissue fixation, it has been applied to the various stages of tissue processing as well as to a wide variety of staining procedures. This use of MWs has not only resulted in drastic reductions in the time required for tissue fixation, processing and staining, but have also produced better cytologic images in cryostat sections, and more importantly, have resulted in better preservation of cellular antigens.

Scattering and coupling effects of electromagnetic waves in 3D networks of spheres

1998 ◽  
Vol 1 (1) ◽  
pp. 45-52 ◽  
Author(s):  
M. Defos du Rau ◽  
F. Pessan ◽  
G. Ruffie ◽  
V. Vignéras-Lefebvre ◽  
J. P. Parneix
Keyword(s):  
Electromagnetic Waves ◽  
Coupling Effects ◽  
3D Networks
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