384,782 research outputs found
Electromagnetic backscattering by corner reflectors
The Geometrical Theory of Diffraction (GTD), which supplements Geometric Optics (GO), and the Physical Theory of Diffraction (PTD), which supplements Physical Optics (PO), are used to predict the backscatter cross sections of dihedral corner reflectors which have right, obtuse, or acute included angles. These theories allow individual backscattering mechanisms of the dihedral corner reflectors to be identified and provide good agreement with experimental results in the azimuthal plane. The advantages and disadvantages of the geometrical and physical theories are discussed in terms of their accuracy, usefulness, and complexity. Numerous comparisons of analytical results with experimental data are presented. While physical optics alone is more accurate and more useful than geometrical optics alone, the combination of geometrical optics and geometrical diffraction seems to out perform physical optics and physical diffraction when compared with experimental data, especially for acute angle dihedral corner reflectors
Research on physical and physiological aspects of visual optics in space flight
Physical and physiological aspects of visual optics in space fligh
Topological superfluid in one-dimensional spin-orbit coupled atomic Fermi gases
ARC Centre of Excellence for Quantum-Atom Optics, Centre for Atom Optics and
Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne 3122,
AustraliaComment: 7 pages, 8 figures; submitted to Physical Review
Physical optics for oven-plate scattering prediction
An oven assembly design is described, which will be used to determine the effects of temperature on the electrical properties of materials which are used as coatings for metal plates. Experimentally, these plates will be heated to a very high temperature in the oven assembly, and measured using a microwave reflectance measurement system developed for the NASA Lewis Research Center, Near-Field Facility. One unknown in this measurement is the effect that the oven assembly will have on the reflectance properties of the plate. Since the oven will be much larger than the plate, the effect could potentially be significant as the size of the plate becomes smaller. Therefore, it is necessary to predict the effect of the oven on the measurement of the plate. A method for predicting the oven effect is described, and the theoretical oven effect is compared to experimental results of the oven material. The computer code which is used to predict the oven effect is also described
Optical realization of relativistic non-Hermitian quantum mechanics
Light propagation in distributed feedback optical structures with gain/loss
regions is shown to provide an accessible laboratory tool to visualize in
optics the spectral properties of the one-dimensional Dirac equation with
non-Hermitian interactions. Spectral singularities and PT symmetry breaking of
the Dirac Hamiltonian are shown to correspond to simple observable physical
quantities and related to well-known physical phenomena like resonance
narrowing and laser oscillation.Comment: 4 page
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