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Light Propagation in Anisotropic Crystals
Published in Shekhar Guha, Leonel P. Gonzalez, Laser Beam Propagation in Nonlinear Optical Media, 2017
Shekhar Guha, Leonel P. Gonzalez
Light propagates in vacuum with a constant speed c, which is given by (ε0μ0)−1/2, with ε0, the vacuum permittivity, equal to 8.85 × 10−12CV−1m−1 and μ0, the vacuum permeability, equal to 4π × 10−7Vs2C−1m−1. In material media, the speed of light (υ) depends on the properties of the medium, with υ equal to c/n, where n, the refractive index of the medium, depends on the properties of the medium. Gases, liquids, most glasses and some crystalline solids are optically isotropic, and in these media the value of n is independent of the propagation direction of light. However, many other optically transparent solids are optically anisotropic because of their anisotropic crystalline structure, and for light propagation in them, the value of n is not the same for all directions of propagation. Moreover, the allowed directions of oscillation of the electric and the magnetic fields in anisotropic media also depend on the propagation direction.
Light Propagation in Anisotropic Crystals
Published in Glen D. Gillen, Katharina Gillen, Shekhar Guha, Light Propagation in Linear Optical Media, 2017
Glen D. Gillen, Katharina Gillen, Shekhar Guha
Light propagates in vacuum with a constant speed c, which is given by (∈0µ0)−1/2, with∈0, the vacuum permittivity, equal to 8.85 × 10−12CV−1m−1 and µ0, the vacuum permeability, equal to 4π × 10−7Vs2C−1m−1. In material media, the speed of light (v) depends on the properties of the medium, with v equal to c/n, where n, the refractive index of the medium, depends on the properties of the medium. Gases, liquids, most glasses, and some crystalline solids are optically isotropic, and in these media the value of n is independent of the propagation direction of light. However, many other optically transparent solids are optically anisotropic because of their anisotropic crystalline structure, and for light propagation in them, the value of n is not the same for all directions of propagation. Moreover, the allowed directions of oscillation of the electric and the magnetic fields in anisotropic media also depend on the propagation direction.
An inverse problem of a simultaneous reconstruction of the dielectric constant and conductivity from experimental backscattering data
Published in Inverse Problems in Science and Engineering, 2021
Vo Anh Khoa, Grant W. Bidney, Michael V. Klibanov, Loc H. Nguyen, Lam H. Nguyen, Anders J. Sullivan, Vasily N. Astratov
Suppose that we only consider non-magnetic targets. Then their relative permeability has to be unity. With being the vacuum permittivity and vacuum permeability, respectively, and , (1) becomes In (2), the fraction is essentially close to the so-called characteristic impedance of free space , which is approximately 377 (). Denote as the dielectric constant. We therefore rewrite the Helmholtz equation (2) and impose the Sommerfeld radiation condition:
Simulation and Experimental Study on Pressure Transfer Mechanism in Multitooth Magnetic Fluid Seals
Published in Tribology Transactions, 2021
Hongming Zhou, Yibiao Chen, Yanjuan Zhang, Decai Li
The magnetic field is solved by the finite element method in ANSYS software. The permeability of the fluid is specified as the vacuum permeability in the magnetic field simulation when the fluid is magnetization saturated. The magnetic forces in the x-axis direction and z-axis direction are obtained by substituting the finite element method result in Eq. [3]. The coercivity and relative permeability of the N35 permanent magnet are 971 kA/m and 1.09, respectively. The relative permeabilities of 304 stainless steel and 20Cr13 stainless steel are equal to 1 and 480, respectively. The element size in the sealing clearance is set to 0.01 mm to get a more accurate result. The element is defined by eight nodes and there are four degrees of freedom on each node, including the z component of the magnetic vector potential, time-integrated electric scalar potential, electric current, and electromotive force.
Reduction of the classical electromagnetism to a two-dimensional curved surface
Published in Journal of Modern Optics, 2019
The description of light propagation in thin structures or along curved surfaces becomes more and more important due to increasing miniaturization in optoelectronics and intensive development of nanophysics. For this description, two-dimensional reduced theory of electromagnetism (19–21) is often used as a model. The situation in an open wave-guide to a certain extent may be mimicked in that way but with certain limitations established in our previous work (12). On the other hand, it should be pointed out that in the case of SPPs the TM modes are the only ones that propagate along the surface (corresponding TE modes do not arise due to the boundary conditions), and cannot be described at all by the usual form of the 2D electromagnetism with the standard Lagrangian where Here and below we use the system of units, where . In this system, the vacuum permeability is the inverse of permittivity: which leads to some simplification of equations. If the theory is to be applied to the propagation in some media, the formulas should be supplemented by the dielectric constant ε or relative permeability μ in an obvious way.