Subwavelength imaging with planar lenses, and electromagnetic energy and forces in metamaterials
Abstract
A planar slab lens can allow subwavelength imaging and is convenient to fabricate. Theoretical and numerical studies of near-field subwavelength imaging properties of isotropic and anisotropic planar slab lenses are presented. The influence of dielectric constant and thickness on performance of an isotropic negative dielectric constant slab is investigated. A cost function based on the plane-wave transfer function is used to evaluate the planar slab lens performance. The imaging properties of a uniaxial anisotropic slab lens are studied as a function of the structure parameters. While hypothetical parameters yield various levels of performance, a design principle to achieve good subwavelength resolution is suggested. The impact of surface roughness on the effective dielectric constant and subwavelength image resolution of a multilayer metal-insulator stack lens is also studied. A general expression for the electromagnetic energy density in a lossy dispersive medium, applicable for a field having a narrow temporal frequency bandwidth, is derived and compared with numerical results for an example dielectric constant. An exact separation of energy into stored and lost energies is shown to be possible in a special case when the wave impedance is independent of frequency. The electromagnetic plane wave force on materials having the possible set of constitutive parameter signs is evaluated. It is shown that a uniform plane wave can exert a negative force on a medium with gain. The electromagnetic force on an infinite planar slab having different constitutive parameters and embedded inside a background material with complex impedance is also investigated.
Degree
Ph.D.
Advisors
Webb, Purdue University.
Subject Area
Electromagnetics|Optics
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