Leaky mode solar receiver using continuous wedge lens
A leaky travelling wave array of optical elements provide a solar wavelength rectenna.
1. A solar energy apparatus comprising:
a waveguide having a top surface, a bottom surface, a detection end, and a collection end;
a continuous wedge lens disposed adjacent the top surface of the waveguide and coextensive with the waveguide to extend along a major axis thereof, for providing solar wavelength light to the waveguide with both a vertical polarization (V-pol) and horizontal polarization (H-pol);
a coupling layer disposed between and co-extensive with the waveguide and the continuous wedge lens, to provide operation in a leaky solar energy receive mode, the coupling layer having a tapered thickness that decreases from the detection end to the collection end; and
a bottom layer formed of a dielectric material, disposed beneath the waveguide adjacent the bottom surface of the waveguide, the bottom layer having a permittivity constant greater than a permittivity constant of the waveguide such that
the bottom layer equalizes H-pol and V-pol velocities within the apparatus.
2. The apparatus of claim 1 wherein the waveguide is a slab.
3. The apparatus of claim 2 wherein a dispersion correcting wedge is disposed beneath the slab to correct for dispersion introduced by the continuous wedge lens.
4. The apparatus of claim 1 wherein a quadratic phase weight is provided by a weighting layer having a tapered thickness that decreases in thickness from the detection end to the collection end.
5. The apparatus of claim 1 wherein the bottom layer has a tapered thickness that increases from the detection end to the collection end.
6. The apparatus of claim 1 wherein the coupling layer decreases in thickness as distance from the detection end.
7. The apparatus of claim 1 wherein the wedge is isotropic.
8. The apparatus of claim 1 wherein the coupling layer provides increasing coupling between the waveguide and the wedge lens as a function of distance along a main axis of the waveguide.
9. The apparatus of claim 1 wherein the coupling layer has a dielectric constant that tapers from the detection end to the collection end.