Showing papers by "David Schurig published in 2005"

Gradient index metamaterials.

Abstract: Metamaterials—artificially structured materials with tailored electromagnetic response—can be designed to have properties difficult or impossible to achieve with traditional materials fabrication methods. Here we present a structured metamaterial, based on conducting split ring resonators sSRRsd, which has an effective index of refraction with a constant spatial gradient. We experimentally confirm the gradient by measuring the deflection of a microwave beam by a planar slab of the composite metamaterial over a range of microwave frequencies. The gradient index metamaterial may prove an advantageous alternative approach to the development of gradient index lenses and similar optics, especially at higher frequencies. In particular, the gradient index metamaterial we propose may be suited for terahertz applications, where the magnetic resonant response of SRRs has recently been demonstrated.

Negative index lens aberrations

Abstract: We examine the Seidel aberrations of thin spherical lenses composed of media with refractive index not restricted to be positive. We find that consideration of this expanded parameter space allows for the reduction or elimination of more aberrations than is possible with only positive index media. In particular, we find that spherical lenses possessing real aplanatic focal points are possible only with a negative index. We perform ray tracing, using a custom code that relies only on Maxwell's equations and conservation of energy, that confirms the results of the aberration calculations.

Sub-diffraction imaging with compensating bilayers

Abstract: We derive a general expression for the material properties of a compensating bilayer, which is a pair of material layers which transfer the field distribution from one side of the bilayer to the other with resolution limited only by the deviation of the material properties from specified values. One of the layers can be free space, a special case of which is the perfect lens, but the layers need not have equal thickness. Compensating a thick layer of free space with a thin layer creates a focusing device with increased working distance, and employs an anisotropic material. It is also possible to achieve compensation of materials with property tensors that are neither positive nor negative definite. In this case, we refer to such media as indefinite, and we analyse, in detail, bilayers of these media which support coupling of internal propagating waves to incident waves of any transverse wave vector. In this case, we find that the enhanced spatial resolution provided by large transverse wave vectors is far less sensitive to loss than that of the perfect lens.

Fabrication and optical measurements of nanoscale meta-materials: terahertz and beyond

Abstract: This paper reports on efforts to create fully left-handed meta-materials at multi-THz frequencies, detailed optical characterizations of various structures fabricated, and understanding to date of what the materials limitations are for making these structures smaller and smaller Presently, authors are using CXRO's nano-writer to create sub-micron structures with 60 nm smallest features Present results on these and other nano-fabricated structures with resonance frequencies in the 100 THz and higher range

Negative Index Lenses

Abstract: The prelims comprise: Introduction Geometric Optics Gaussian Optics Aberrations References

New optics using negative refraction

Abstract: We summarize the benefits that negative index materials (NIMs), realizable in artificially constructed metamaterials, can have on both geometrical and wave optics. NIMs may lead to novel or improved future optical devices.