Patent ID: 8634144

Claim:
A method, comprising: coupling to an evanescent electromagnetic wave at an input region; responsive to the coupling, propagating electromagnetic energy in an electromagnetic field from a first surface within the input region to a second surface within an output region, where the first and second surfaces are substantially planar and substantially parallel, and where the propagating includes: inducing a first polarization in a first direction, the first polarization positively corresponding to a first component of the electromagnetic field in the first direction; and inducing a second polarization in a second direction perpendicular to the first direction, the second polarization negatively corresponding to a second component of the electromagnetic field in the second direction; and providing the propagated electromagnetic energy as a non-evanescent electromagnetic wave at the output region; and wherein: the coupling to the evanescent electromagnetic wave is a coupling to the evanescent electromagnetic wave at a first frequency with a first wavenumber, and the providing of the non-evanescent electromagnetic wave is a providing of 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 and the second wavenumber corresponding to a surface parallel direction of the second surface; the first and second surfaces define an interior region intermediate the first and second surfaces, a first exterior region outside the interior region and adjacent to the first surface 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 exterior region outside the interior region and adjacent to the second surface defines a second phase velocity for electromagnetic radiation, and the second wavenumber is less than the first frequency divided by the second phase velocity.