Tapered Optical Waveguide Coupled to Plasmonic Grating Structure
There is provided an optical waveguide comprising: a periodic component comprising a plurality of material elements ( 101 ) arranged to receive radiation; and a plurality of tapered waveguides ( 103 ), wherein each material element is respectively coupled to a tapered waveguide which tapers outwardly from the material element. The device works as a broadband absorber.
1 . An optical waveguide comprising:
a periodic component comprising a plurality of material elements arranged to receive radiation; and
a plurality of tapered waveguides, wherein each material element is respectively coupled to a tapered waveguide which tapers outwardly from the material element.
2 . An optical waveguide as claimed in claim 1 wherein the plurality of material elements and/or plurality of tapered waveguides are metamaterials.
3 . An optical waveguide as claimed in claim 1 wherein the material elements and/or tapered waveguides are plasmonic.
4 . An optical waveguide as claimed in claim 1 wherein the material elements and/or tapered waveguides comprise a material having a negative dielectric permittivity.
5 . An optical waveguide as claimed in claim 1 wherein the material elements and/or tapered waveguides are metallic, optionally, at least one selected from the group comprising: gold, silver and alumina.
6 . An optical waveguide as claimed in claim 1 wherein the periodic component has a first dimension no greater than a wavelength of the received radiation.
7 . An optical waveguide as claimed in claim 1 wherein each material element has a first dimension no greater than a wavelength of the received radiation.
8 . An optical waveguide as claimed in claim 1 wherein the first dimension is between 1 nm and 8 μm.
9 . An optical waveguide as claimed in claim 1 wherein the spacing between adjacent material elements is between 1 nm and 8 μm.
10 . An optical waveguide as claimed in claim 1 wherein the plurality of material elements are arranged in a two-dimensional array on a first plane.
11 . An optical waveguide as claimed in claim 1 wherein the tapered waveguides taper outwardly from the first plane to a second plane.
12 . An optical waveguide as claimed in claim 1 wherein the second plane comprises a reflector.
13 . An optical waveguide as claimed in claim 1 wherein the material elements are symmetric in two orthogonal directions.
14 . An optical waveguide as claimed in claim 1 wherein the optical waveguide is passive.
15 . A photovoltaic device comprising an optical waveguide as claimed in claim 1 .
16 . A photovoltaic device as claimed in claim 15 further comprising:
a photovoltaic component interleaved between the tapered waveguides.
17 . A photovoltaic device as claimed in claim 16 wherein the photovoltaic component is arranged to absorb light guided by the optical waveguide.
18 . A photovoltaic device as claimed in claim 16 wherein the photovoltaic component has a shaped complementary to the tapered waveguides.
19 . A photovoltaic device as claimed in claim 16 wherein photovoltaic component is formed of least one selected from the group comprising: silicon, germanium, gallium arsenide and silicon carbide.
20 . A photovoltaic device as claimed in claim 15 wherein the photovoltaic device is a solar cell.
21 . (canceled)