Low-Loss and Broadband Metamaterials for Negative Index and Transformational Optics Applications

Our focus has been on the design and analysis of metamaterials that will lead to the realization of new classes of devices. In large part, the materials are not defined by lithography, and hence are amenable to inexpensive large-scale manufacture. Nonlinear optimization methods have been used to design structures that are based on anisotropic metamaterials and operate as efficient energy collectors (anti-reflection coatings) and cloaks. Active quantum dot metamaterials have yielded controllable transmission windows, and this material forms the basis of a nanophotonic source. A graphene stack is proposed that appears to be the blackest material, and an experimental effort has started with a collaborator. Magnetism based on carbon nanotube coils is providing new insight into magnetic metamaterials. A study of electromagnetic energy in dispersive materials has produced some surprising results. A rigorous study of electromagnetic forces in positive and negative refractive index materials shows that a negative force occurs in a material with gain. Imaging and antenna opportunities are described for metal-insulator stack lenses, and analytic models are developed for curved stacks that can be used in design. The influence of surface roughness on the homogenized anisotropic response of metal-insulator stacks is evaluated.
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