Photonic crystal Raman sensors and methods including the same

• US 20070252981A1
• Filed: 04/27/2006
• Published: 11/01/2007
• Est. Priority Date: 04/27/2006
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Li, Zhiyong, Stewart, Duncan, Beausoleil, Raymond, Spillane, Sean
• Granted Patent: US 7,466,407 B2
• Time in Patent Office: Days
• US Class Current: 356/301
• CPC Class Codes: G01J 3/44 Raman spectrometry; Scattering spectrometry ; Fluorescence spectrometry
• CPC Class Codes: G01N 21/658 enhancement Raman, e.g. surface plasmons

Abstract

Raman-enhancing structures include a photonic crystal having a resonant cavity and at least one waveguide coupled to the resonant cavity. A nanostructure comprising a Raman-enhancing material is disposed proximate the resonant cavity of the photonic crystal. Raman-enhancing structures include a microdisk resonator, at least one waveguide coupled to the microdisk resonator, and a nanostructure comprising a Raman-enhancing material disposed proximate the microdisk resonator. Methods for performing Raman spectroscopy include generating radiation, guiding the radiation through a waveguide to a resonant cavity in a photonic crystal or a microdisk resonator, resonating the radiation in the resonant cavity or microdisk resonator, providing an analyte proximate the resonant cavity or microdisk resonator, subjecting the analyte to the resonating radiation, and detecting Raman scattered radiation.

Claims

1. A Raman-enhancing structure comprising:

a photonic crystal comprising;

a resonant cavity; and

at least one waveguide coupled to the resonant cavity; and

a nanostructure comprising a Raman-enhancing material disposed proximate the resonant cavity of the photonic crystal.

2. A Raman-enhancing structure as recited in claim 1, wherein the resonant cavity comprises a point defect in the photonic crystal, and wherein the waveguide comprises a line defect in the photonic crystal.

3. A Raman-enhancing structure as recited in claim 2, wherein the photonic crystal comprises a two-dimensional photonic crystal.

4. A Raman-enhancing structure as recited in claim 3, wherein the photonic crystal comprises a plurality of cylindrical regions dispersed periodically in an array of rows throughout a matrix, a majority of the cylindrical regions having a uniform radius, the cylindrical regions exhibiting a first dielectric constant and the matrix exhibiting a second dielectric constant that differs from the first dielectric constant.

5. A Raman-enhancing structure as recited in claim 4, wherein the resonant cavity comprises one cylindrical region of the plurality of cylindrical regions, the one cylindrical region of the resonant cavity having a radius differing from the uniform radius of the majority of the cylindrical regions.

6. A Raman-enhancing structure as recited in claim 4, wherein each cylindrical region of the plurality of cylindrical regions comprises air.

7. A Raman-enhancing structure as recited in claim 4, wherein the matrix comprises air.

8. A Raman-enhancing structure as recited in claim 4, wherein the cylindrical regions are arranged in a square lattice or a triangular lattice.

9. A Raman-enhancing structure as recited in claim 1, wherein the photonic crystal comprises a plurality of resonant cavities, the at least one waveguide being coupled to each resonant cavity of the plurality of resonant cavities.

10. A Raman-enhancing structure as recited in claim 1, wherein the nanostructure comprises at least two nanoparticles disposed within the resonant cavity of the photonic crystal, each nanoparticle comprising a Raman-enhancing material.

11. A Raman-enhancing structure as recited in claim 1, wherein the photonic crystal further comprises an additional waveguide coupled to the resonant cavity.

12. A Raman-enhancing structure as recited in claim 1, further comprising an analyte disposed proximate the resonant cavity of the photonic crystal and the nanostructure.

13. A Raman-enhancing structure as recited in claim 1, wherein the resonant cavity is configured to resonate incident electromagnetic radiation.

14. A Raman-enhancing structure as recited in claim 1, wherein the resonant cavity is configured to resonate Raman-scattered radiation.

15. A Raman-enhancing structure comprising:

a microdisk resonator;

at least one waveguide coupled to the microdisk resonator; and

a nanostructure comprising a Raman-enhancing material disposed proximate the microdisk resonator.

16. A Raman-enhancing structure as recited in claim 15, further comprising a plurality of microdisk resonators, each microdisk resonator being configured to resonate different wavelengths of electromagnetic radiation.

17. A Raman-enhancing structure as recited in claim 15, further comprising an additional waveguide coupled to the microdisk resonator.

18. A Raman-enhancing structure as recited in claim 15, wherein the nanostructure comprises two or more nanoparticles, each nanoparticle comprising a Raman-enhancing material.

19. A Raman-enhancing structure as recited in claim 15, wherein the microdisk resonator is configured to resonate incident electromagnetic radiation.

20. A Raman-enhancing structure as recited in claim 15, wherein the microdisk resonator is configured to resonate Raman-scattered radiation.

21. A method for performing Raman spectroscopy comprising:

generating electromagnetic radiation;

guiding the electromagnetic radiation through a waveguide in a photonic crystal to a resonant cavity in the photonic crystal;

resonating the electromagnetic radiation within the resonant cavity;

providing an analyte proximate the resonant cavity;

subjecting the analyte to the resonating electromagnetic radiation; and

detecting Raman scattered radiation scattered by the analyte.

22. A method for performing Raman spectroscopy as recited in claim 21, further comprising providing a nanostructure comprising a Raman-enhancing material proximate the resonant cavity and the analyte.

23. A method for performing Raman spectroscopy comprising:

generating electromagnetic radiation;

guiding the electromagnetic radiation through a waveguide to a microdisk resonator;

resonating the electromagnetic radiation within the microdisk resonator;

providing an analyte proximate the microdisk resonator;

subjecting the analyte to the resonating electromagnetic radiation; and

detecting Raman scattered radiation scattered by the analyte.

24. A method as recited in claim 23, further comprising providing a nanostructure comprising a Raman-enhancing material proximate the microdisk resonator and the analyte.