Masud Mansuripur | The University of Arizona (original) (raw)
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Papers by Masud Mansuripur
IEEE Transactions on Magnetics, 1991
ABSTRACT Computer simulations of the microscopic magnetic dynamics of thin films provides a means... more ABSTRACT Computer simulations of the microscopic magnetic dynamics of thin films provides a means for developing theoretical understanding of the behavior of magnetic recording materials and a way of relating material parameters to magnetic behavior. Such simulations have become possible because of the availability of high-performance supercomputers (such as the Connection Machine) and by improvements in algorithms for evaluating magnetic interactions. The proper implementation of the Fourier technique on a two-dimensional hexagonal lattice is described. A naive transcription of the method as used for a rectangular lattice leads to serious aliasing problems for short wavelengths. The implementation described reduces these effects.
Optics and Photonics News, 1999
Optics and Photonics News, 1999
Optics and Photonics News, 1999
ABSTRACT
Optics and Photonics News, 1998
ABSTRACT
Optics and Photonics News, 1998
ABSTRACT
Optics and Photonics News, 1998
Optics and Photonics News, 1998
Optics and Photonics News, 1998
ABSTRACT
Optics and Photonics News, 2000
Optics and Photonics News, 2000
ABSTRACT
Optics and Photonics News, 2000
Journal of Applied Physics, Aug 15, 1992
Perpendicular magnetoresistance data performed on magneto-optical samples with uniaxial magnetic ... more Perpendicular magnetoresistance data performed on magneto-optical samples with uniaxial magnetic anisotropy (perpendicular to the film plane) show a change of the resistance ΔR/R when the applied field reaches the coercive field. The various mechanisms that can lead to this phenomenon are investigated based on different magneto-optical films. In particular, the interaction of magnetic domains and domain walls with the electric current is interesting. Separating the two effects is important to understanding of the various galvanomagnetic and magnetic processes in these films. Three different mechanisms are considered in order to explain the data: The first mechanism is associated with the Hall effect, the second mechanism involves the anisotropic resistivity, and the third mechanism is related to the s-d scattering effect. Some of the experimental results are explained by modeling the current and electric-field distribution in these films. In the simulations the film is modeled by a two- or three-dimensional lattice with each branch in the lattice having its own resistivity tensor in order to simulate magnetic domains and domain walls in the film.
Maxwell's macroscopic equations combined with a generalized form of the Lorentz law of force are ... more Maxwell's macroscopic equations combined with a generalized form of the Lorentz law of force are a complete and consistent set of equations. Not only are these five equations fully compatible with special relativity, they also conform with conservation laws of energy, momentum, and angular momentum. We demonstrate consistency with the conservation laws by showing that, when a beam of light enters a magnetic dielectric, a fraction of the incident linear (or angular) momentum pours into the medium at a rate determined by the Abraham momentum density, ExH/c^2, and the group velocity V_g of the electromagnetic field. The balance of the incident, reflected, and transmitted momenta is subsequently transferred to the medium as force (or torque) at the leading edge of the beam, which propagates through the medium with velocity V_g. Our analysis does not require "hidden" momenta to comply with the conservation laws, nor does it dissolve into ambiguities with regard to the nature of electromagnetic momentum in ponderable media. The linear and angular momenta of the electromagnetic field are clearly associated with the Abraham momentum, and the phase and group refractive indices (n_p and n_g) play distinct yet definitive roles in the expressions of force, torque, and momentum densities.
Proceedings of Spie the International Society For Optical Engineering, 2007
We present arguments in favor of the proposition that the momentum of light inside a transparent ... more We present arguments in favor of the proposition that the momentum of light inside a transparent dielectric medium is the arithmetic average of the Minkowski and Abraham momenta. Using the Lorentz transformation of the fields (and of the coordinates) from a stationary to a moving reference frame, we show the consistent transformation of electromagnetic energy and momentum between the two frames. We also examine the momentum of static (i.e., time-independent) electromagnetic fields, and show that the close connection that exists between the Poynting vector and the momentum density extends all the way across the frequency spectrum to this zero-frequency limit. In the specific example presented in this paper, the static field inside a non-absorbing dielectric material turns out to have the Minkowski momentum.
Optical Data Storage, 1992
Optical Trapping and Optical Micromanipulation IV, 2007
Proceedings of Spie the International Society For Optical Engineering, 2007
A combination of ray-tracing and diffraction theory is used to model the diffractive optical elem... more A combination of ray-tracing and diffraction theory is used to model the diffractive optical elements used in optical data storage systems. Details of the theoretical model and some numerical simulation results are presented.
IEEE Transactions on Magnetics, 1991
ABSTRACT Computer simulations of the microscopic magnetic dynamics of thin films provides a means... more ABSTRACT Computer simulations of the microscopic magnetic dynamics of thin films provides a means for developing theoretical understanding of the behavior of magnetic recording materials and a way of relating material parameters to magnetic behavior. Such simulations have become possible because of the availability of high-performance supercomputers (such as the Connection Machine) and by improvements in algorithms for evaluating magnetic interactions. The proper implementation of the Fourier technique on a two-dimensional hexagonal lattice is described. A naive transcription of the method as used for a rectangular lattice leads to serious aliasing problems for short wavelengths. The implementation described reduces these effects.
Optics and Photonics News, 1999
Optics and Photonics News, 1999
Optics and Photonics News, 1999
ABSTRACT
Optics and Photonics News, 1998
ABSTRACT
Optics and Photonics News, 1998
ABSTRACT
Optics and Photonics News, 1998
Optics and Photonics News, 1998
Optics and Photonics News, 1998
ABSTRACT
Optics and Photonics News, 2000
Optics and Photonics News, 2000
ABSTRACT
Optics and Photonics News, 2000
Journal of Applied Physics, Aug 15, 1992
Perpendicular magnetoresistance data performed on magneto-optical samples with uniaxial magnetic ... more Perpendicular magnetoresistance data performed on magneto-optical samples with uniaxial magnetic anisotropy (perpendicular to the film plane) show a change of the resistance ΔR/R when the applied field reaches the coercive field. The various mechanisms that can lead to this phenomenon are investigated based on different magneto-optical films. In particular, the interaction of magnetic domains and domain walls with the electric current is interesting. Separating the two effects is important to understanding of the various galvanomagnetic and magnetic processes in these films. Three different mechanisms are considered in order to explain the data: The first mechanism is associated with the Hall effect, the second mechanism involves the anisotropic resistivity, and the third mechanism is related to the s-d scattering effect. Some of the experimental results are explained by modeling the current and electric-field distribution in these films. In the simulations the film is modeled by a two- or three-dimensional lattice with each branch in the lattice having its own resistivity tensor in order to simulate magnetic domains and domain walls in the film.
Maxwell's macroscopic equations combined with a generalized form of the Lorentz law of force are ... more Maxwell's macroscopic equations combined with a generalized form of the Lorentz law of force are a complete and consistent set of equations. Not only are these five equations fully compatible with special relativity, they also conform with conservation laws of energy, momentum, and angular momentum. We demonstrate consistency with the conservation laws by showing that, when a beam of light enters a magnetic dielectric, a fraction of the incident linear (or angular) momentum pours into the medium at a rate determined by the Abraham momentum density, ExH/c^2, and the group velocity V_g of the electromagnetic field. The balance of the incident, reflected, and transmitted momenta is subsequently transferred to the medium as force (or torque) at the leading edge of the beam, which propagates through the medium with velocity V_g. Our analysis does not require "hidden" momenta to comply with the conservation laws, nor does it dissolve into ambiguities with regard to the nature of electromagnetic momentum in ponderable media. The linear and angular momenta of the electromagnetic field are clearly associated with the Abraham momentum, and the phase and group refractive indices (n_p and n_g) play distinct yet definitive roles in the expressions of force, torque, and momentum densities.
Proceedings of Spie the International Society For Optical Engineering, 2007
We present arguments in favor of the proposition that the momentum of light inside a transparent ... more We present arguments in favor of the proposition that the momentum of light inside a transparent dielectric medium is the arithmetic average of the Minkowski and Abraham momenta. Using the Lorentz transformation of the fields (and of the coordinates) from a stationary to a moving reference frame, we show the consistent transformation of electromagnetic energy and momentum between the two frames. We also examine the momentum of static (i.e., time-independent) electromagnetic fields, and show that the close connection that exists between the Poynting vector and the momentum density extends all the way across the frequency spectrum to this zero-frequency limit. In the specific example presented in this paper, the static field inside a non-absorbing dielectric material turns out to have the Minkowski momentum.
Optical Data Storage, 1992
Optical Trapping and Optical Micromanipulation IV, 2007
Proceedings of Spie the International Society For Optical Engineering, 2007
A combination of ray-tracing and diffraction theory is used to model the diffractive optical elem... more A combination of ray-tracing and diffraction theory is used to model the diffractive optical elements used in optical data storage systems. Details of the theoretical model and some numerical simulation results are presented.