Nano-fabricated plasmonic optical transformer
The present invention provides a plasmonic optical transformer to produce a highly focuses optical beam spot, where the transformer includes a first metal layer, a dielectric layer formed on the first metal layer, and a second metal layer formed on the dielectric layer, where the first metal layer, the dielectric layer, and the second layer are patterned to a shape including a first section having a first cross section, a second section following the first section having a cross-section tapering from the first section to a smaller cross-section, and a third section following the second section having a cross-section matching the tapered smaller cross-section of the second section.
1. An optical transformer comprising:
a first metal layer;
a dielectric layer disposed on the first metal layer, the dielectric layer being in a shape comprising:
a first section having a first thickness of about 100 nanometers and a first width,
a second section coupled to the first section having a tapering thickness tapering at a thickness taper angle θ from the first thickness to a smaller thickness of about 15 nanometers to 20 nanometers and having a tapering width from the first width to a smaller width, and
a third section having the smaller thickness and the smaller width coupled to the second section; and
a second metal layer disposed on the dielectric layer.
2. The optical transformer of claim 1 wherein the first metal layer comprises at least one of Au, Ag, Cu, Al, and a high conductivity metal.
3. The optical transformer of claim 1 wherein the first metal layer is approximately 50 nanometers thick.
4. The optical transformer of claim 1 wherein the dielectric layer comprises at least one of a polymer, SiO2, SiO, SiOx, and Si3N4, where x is a non-integer number.
5. The optical transformer of claim 1 wherein the thickness taper angle θ is between about 5 degrees and 90 degrees.
6. The optical transformer of claim 1 wherein a thickness of the dielectric layer in the second section varies from the first thickness to the smaller thickness.
7. The optical transformer of claim 1 wherein the first width is about 100 nanometers, wherein the smaller width is about 15 nanometers to 20 nanometers, and wherein a width of the second section varies from the first width to the smaller width.
8. The optical transformer of claim 1 wherein the thickness tapering angle θ varies over a range from 0 degrees to a specified value.
9. A method of making an optical transformer comprising:
providing a first metal layer;
forming a dielectric layer on the first metal layer, the dielectric layer being in a shape comprising:
a first section having a first thickness of about 100 nanometers and a first width,
a second section coupled to the first section having a tapering thickness tapering at a thickness taper angle θ from the first thickness to a smaller thickness of about 15 nanometers to 20 nanometers and having a tapering width from the first width to a smaller width, and
a third section having the smaller thickness and the smaller width coupled to the second section; and
forming a second metal layer on the dielectric layer.
10. The method of claim 9 wherein the first metal layer comprises at least one of Au, Ag, Cu, Al, and a high conductivity metal.
11. The method of claim 9 wherein the first metal layer is approximately 50 nanometers thick.
12. The method of claim 9 wherein the dielectric layer comprises at least one of a polymer, SiO2, SiO, SiOx, and Si3N4, where x is a non-integer.
13. The method of claim 9 wherein forming the dielectric layer includes forming the tapering thickness in the dielectric layer in the second section by a selective electron-beam induced deposition process.
14. The method of claim 9 wherein the thickness taper angle θ is between about 5 degrees and 90 degrees.
15. The method of claim 9 wherein forming the dielectric layer includes forming the dielectric layer such that a thickness of the dielectric layer in the second section varies from the first thickness to the smaller thickness.
16. The method of claim 9 wherein the first width is about 100 nanometers, wherein the smaller width is about 15 nanometers to 20 nanometers, and wherein a width of the second section varies from the first width to the smaller width.
17. The method of claim 9 further comprising:
patterning the widths of the optical transformer by focused ion beam milling.
18. The method of claim 9 wherein the thickness tapering angle θ is variable over a range from 0 degrees to a specified value.
19. The optical transformer of claim 1 wherein the optical transformer is associated with an optical read/write device configured to write and/or read data from an optical storage medium.
20. The optical transformer of claim 1 wherein the optical transformer is configured to read and write data to and/or from an optical storage medium by coupling a light signal to the optical storage medium.
21. The optical transformer of claim 1 wherein the optical transformer is associated with a device configured to perform optical spectroscopy.
22. The optical transformer of claim 1 wherein the second metal layer comprises at least one of Au, Ag, Cu, Al, and a high conductivity metal.
23. The optical transformer of claim 1 wherein the second metal layer is approximately 50 nanometers thick.
24. The method of claim 9 wherein the second metal layer comprises at least one of Au, Ag, Cu, Al, and a high conductivity metal.
25. The method of claim 9 wherein the second metal layer is approximately 50 nanometers thick.
26. The optical transformer of claim 1 wherein a thickness of the first metal layer is substantially uniform, and wherein a thickness of the second metal layer is substantially uniform.
27. The method of claim 9 wherein a thickness of the first metal layer is substantially uniform, and wherein a thickness of the second metal layer is substantially uniform.
28. An optical transformer comprising:
a first metal layer;
a dielectric layer disposed on the first metal layer, the dielectric layer being in a shape comprising:
a first section having a first thickness and a first width of about 100 nanometers,
a second section coupled to the first section having a tapering thickness tapering at a thickness taper angle θ from the first thickness to a smaller thickness and having a tapering width from the first width to a smaller width of about 15 nanometers to 20 nanometers, a width of the second section varying from the first width to the smaller width, and
a third section having the smaller thickness and the smaller width coupled to the second section; and
a second metal layer disposed on the dielectric layer.