Patent ID: 8634141

Claim:
An electromagnetic apparatus, comprising: a conversion structure with electromagnetic parameters that include indefinite tensor parameters, the conversion structure being responsive to an evanescent electromagnetic wave at a first surface region to provide a non-evanescent electromagnetic wave at a second surface region, where the first and second surface regions are substantially planar and substantially parallel, and wherein: the conversion structure is responsive to the evanescent electromagnetic wave at a first frequency with a first wavenumber to provide the non-evanescent electromagnetic wave at the first frequency with a second wavenumber, the first wavenumber corresponding to a surface parallel direction of the first surface region and the second wavenumber corresponding to a surface parallel direction of the second surface region; a first region outside the conversion structure and adjacent to the first surface region defines a first phase velocity for electromagnetic radiation, and the first wavenumber is greater than the first frequency divided by the first phase velocity; and a second region outside the conversion structure and adjacent to the second surface region defines a second phase velocity for electromagnetic radiation, and the second wavenumber is less than the first frequency divided by the second phase velocity.