Method and apparatus for controlling light flux with sub-micron plasmon waveguides
View Patent ↗Apparatuses and methods for modulating electromagnetic radiation are disclosed. A plasmon waveguide including an array of metallic nanoparticles disposed on a dielectric substrate is provided. The plasmon waveguide is disposed on a MEMS structure. An electromagnetic radiation signal is applied to a tapered fiber disposed proximate the MEMS structure. The intensity of the electromagnetic radiation signal passing through the tapered fiber is modified by displacing a deformable member of the MEMS structure to modify a distance between the plasmon waveguide and the tapered fiber such that an evanescent field of the tapered fiber causes a plasmon resonance in the plasmon waveguide.
1. An electromagnetic radiation modulator, comprising:
a plasmon waveguide including an array of metallic nanoparticles disposed on a dielectric substrate; and
a MEMS structure disposed near the plasmon waveguide and including a deformable member;
a tapered fiber configured for conveying an electromagnetic radiation signal and including a tapered portion disposed on the deformable member such that an evanescent field from the tapered portion is positioned proximate the plasmon waveguide; and
a control signal operably coupled to the MEMS structure and configured to cause the deformable member to displace such that there is a change in a distance between the plasmon waveguide and the tapered portion.
2. The electromagnetic radiation modulator of claim 1 , wherein the array of metallic nanoparticles is disposed in an arrangement selected from the group consisting of a one-dimensional array and a two-dimensional array.
3. The electromagnetic radiation modulator of claim 1 , wherein the metallic nanoparticles are formed of a material selected from the group consisting of a gold and silver.
4. The electromagnetic radiation modulator of claim 1 , wherein the change in the distance is toward a higher intensity region of the evanescent field or toward a lower intensity region of the evanescent field.
5. The electromagnetic radiation modulator of claim 1 , wherein the deformable member comprises a cantilever member and the tapered portion is disposed near an end of the cantilever member and suspended in a movable position relative to the plasmon waveguide such that a deflection of the cantilever member causes the change in the distance from the plasmon waveguide.
6. The electromagnetic radiation modulator of claim 1 , wherein the deformable member comprises a deflectable bridge-type beam member and the tapered portion is disposed on the bridge-type beam member and suspended in a movable position relative to the plasmon waveguide such that a deflection of the bridge-type beam member causes the change in the distance from the plasmon waveguide.
7. The electromagnetic radiation modulator of claim 1 , wherein:
the MEMS structure further comprises a first plate-shaped member;
the deformable member further comprises a thin deflectable second plate-shaped member disposed proximate the first plate-shaped member, the tapered portion being disposed on the second plate-shaped member and suspended in a movable position relative to the plasmon waveguide; and
at least one support spacer disposed between the first plate-shaped member and the second plate-shaped member;
wherein a deflection of the second plate-shaped member causes the change in the distance from the plasmon waveguide.
8. The electromagnetic radiation modulator of claim 7 , wherein the deflection of the second plate-shaped member is caused by either the control signal applied between the first plate-shaped member and the second plate-shaped member or by a mechanical force applied to the second plate-shaped member.
9. An electromagnetic radiation modulator, comprising:
a tapered fiber including a tapered portion and configured for conveying an electromagnetic radiation signal;
a MEMS structure disposed near the tapered portion and including a deformable member;
a plasmon waveguide comprising an array of metallic nanoparticles disposed on a dielectric substrate, the plasmon waveguide disposed on the deformable member of the MEMS structure such that it is proximate an evanescent field from the tapered portion; and
a control signal operably coupled to the MEMS structure and configured to cause the deformable member to displace such that there is a change in a distance between the plasmon waveguide and the tapered portion.
10. The electromagnetic radiation modulator of claim 9 , wherein the array of metallic nanoparticles is disposed in an arrangement selected from the group consisting of a one-dimensional array and a two-dimensional array.
11. The electromagnetic radiation modulator of claim 9 , wherein the metallic nanoparticles are formed of a material selected from the group consisting of a gold and silver.
12. The electromagnetic radiation modulator of claim 9 , wherein the change in the distance is toward a higher intensity region of the evanescent field or toward a lower intensity region of the evanescent field.
13. The electromagnetic radiation modulator of claim 9 , wherein the deformable member comprises a cantilever member and the plasmon waveguide is disposed near an end of the cantilever member and suspended in a movable position relative to the tapered portion such that a deflection of the cantilever member causes the change in the distance from the tapered portion.
14. The electromagnetic radiation modulator of claim 9 , wherein the deformable member comprises a deflectable bridge-type beam member and the plasmon waveguide is disposed on the bridge-type beam member and suspended in a movable position relative to the tapered portion such that a deflection of the bridge-type beam member causes the change in the distance from the tapered portion.
15. The electromagnetic radiation modulator of claim 9 , wherein:
the MEMS structure further comprises a first plate-shaped member;
the deformable member further comprises a thin deflectable second plate-shaped member disposed proximate the first plate-shaped member, the plasmon waveguide being disposed on the second plate-shaped member and suspended in a movable position relative to the tapered portion; and
at least one support spacer disposed between the first plate-shaped member and the second plate-shaped member;
wherein a deflection of the second plate-shaped member causes the change in the distance from the tapered portion.
16. The electromagnetic radiation modulator of claim 15 , wherein the deflection of the second plate-shaped member is caused by either the control signal applied between the first plate-shaped member and the second plate-shaped member or by a mechanical force applied to the second plate-shaped member.
17. A method for modulating electromagnetic radiation, comprising:
providing a plasmon waveguide comprising an array of metallic nanoparticles disposed on a dielectric substrate, wherein the plasmon waveguide is disposed on a MEMS structure;
applying an electromagnetic radiation signal to a tapered fiber disposed proximate the MEMS structure; and
modifying the intensity of the electromagnetic radiation signal passing through the tapered fiber by displacing a deformable member of the MEMS structure to modify a distance between the plasmon waveguide and the tapered fiber such that an evanescent field of the tapered fiber causes a plasmon resonance in the plasmon waveguide.
18. The method of claim 17 , wherein providing the plasmon waveguide further comprises disposing the array of metallic nanoparticles in an arrangement selected from the group consisting of a one-dimensional array and a two-dimensional array.
19. The method of claim 17 , wherein modifying the intensity is due to a modification of the distance toward a higher intensity region of the evanescent field or toward a lower intensity region of the evanescent field.
20. The method of claim 17 , wherein providing the plasmon waveguide further comprises disposing metallic nanoparticles formed of a material selected from the group consisting of a gold and silver.