Sensors employing nanoparticles and microcavities

• US 6,781,690 B2
• Filed: 03/01/2001
• Issued: 08/24/2004
• Est. Priority Date: 05/17/1999
• Status: Expired due to Fees

• Current Assignee: New Mexico State University Technology Transfer Corporation
• Original Assignee: New Mexico State University Technology Transfer Corporation
• Inventors: Shalaev, Vladimir M., Smith, Harold V., Armstrong, Robert L.
• Primary Examiner(s): Evans, F. L.
• Application Number:
  US09/797,609
• Publication Number:
  US 20020015150A1
• Time in Patent Office: 1,272 Days
• Field of Search: 356/301
• US Class Current: 356/301
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G01N 21/658 enhancement Raman, e.g. surface plasmons
• CPC Class Codes: G02F 1/353 Frequency conversion, i.e. wherein a light beam is generated with frequency components different from those of the incident light beams
• CPC Class Codes: G02F 1/3534 Three-wave interaction, e.g. sum-difference frequency generation G02F1/3532 takes precedence
• CPC Class Codes: G02F 1/3536 Four-wave interaction
• CPC Class Codes: G02F 1/3538 for optical phase conjugation controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation using optical phase conjugation H01S3/10076
• CPC Class Codes: G02F 1/355 characterised by the materials used
• CPC Class Codes: G02F 1/37 for second-harmonic generation G02F1/3532 takes precedence
• CPC Class Codes: G02F 1/39 for parametric generation or amplification of light, infrared or ultraviolet waves
• CPC Class Codes: G02F 2202/36 Micro- or nanomaterials
• CPC Class Codes: G02F 2203/15 involving resonance effects, e.g. resonantly enhanced interaction
• CPC Class Codes: G11B 7/00453 involving spectral or photochemical hole burning
• CPC Class Codes: H01S 3/0602 Crystal lasers or glass lasers H01S3/063 takes precedence
• CPC Class Codes: H01S 3/30 using scattering effects, e.g. stimulated Brillouin or Raman effects

Abstract

An optical sensing enhancing material (and corresponding method of making) comprising: a medium, the medium comprising a plurality of aggregated nanoparticles comprising fractals; and a microcavity, wherein the medium is located in a vicinity of the microcavity. Also an optical sensor and sensing method comprising: providing a doped medium, the medium comprising a plurality of aggregated nanoparticles comprising fractals, with the material; locating the doped medium in the vicinity of a microcavity; exciting the doped medium with a light source; and detecting light reflected from the doped medium.

Claims

1. An optical sensing enhancing material comprising:

a medium, said medium comprising a plurality of aggregated nanoparticles comprising fractals; and

a microcavity, wherein said medium is located in a vicinity of said microcavity.

2. The material of claim 1 additionally comprising an analyte deposited with said medium in the vicinity of said microcavity by a method selected from the group consisting of laser ablation particle deposition, and lithography.

3. The material of claim 2 additionally comprising a non-reactive surface coating placed over said analyte and said medium.

4. A method of making an optical sensing enhancing material, the method comprising the steps of:

providing a microcavity; and

providing to a vicinity of the microcavity a plurality of aggregated nanoparticles comprising fractals.

5. The method of claim 4 additionally comprising the step of depositing an analyte with the medium in the vicinity of the microcavity by a method selected from the group consisting of laser ablation, particle deposition, and lithography.

6. The method of claim 5 additionally comprising the step of placing a non-reactive surface coating over the analyte and the medium.

7. An optical sensor comprising:

a medium, said medium comprising a plurality of aggregated nanoparticles comprising fractals;

a microcavity, wherein said medium is located in a vicinity of said microcavity;

a light source incident on said medium; and

a detector of light reflected from said medium.

8. The optical sensor of claim 7 wherein said detector detects Raman signals.

9. The optical sensor of claim 7 wherein analytes are placed in direct contact with said medium.

10. The optical sensor of claim 7 wherein analytes are remote from said medium.

11. The optical sensor of claim 7 wherein said light source comprises two counterpropogating light sources.

12. The optical sensor of claim 7 wherein said microcavity is selected from the group consisting of quartz tubes and quartz rods.

13. An optical sensing method comprising the steps of;

providing a doped medium, the medium comprising a plurality of aggregated nanoparticles comprising fractals, with a material;

locating the doped medium in the vicinity of a microcavity;

exciting the doped medium with a light source; and

detecting light reflected from said doped medium.

14. The optical sensing method of claim 13 wherein the detecting step comprises detecting Raman signals.

15. The optical sensing method of claim 13 additionally comprising the step of placing analytes in direct contact with the doped medium.

16. The optical sensing method of claim 13 additionally comprising the step of locating analytes remotely from the medium.

17. The optical sensing method of claim 13 wherein in the exciting step the light source comprises two counterpropogating light sources.

18. The optical sensing method of claim 13 wherein in the locating step the microcavity is selected from the group consisting of quartz tubes and quartz rods.

19. A method of detecting a material, the method comprising the steps of:

exciting both the material and a medium in a vicinity of a microcavity, the medium comprising a plurality of aggregated nanoparticles comprising fractals, with at least one light source;

detecting spectroscopic data of the material.

20. The method of claim 19 wherein the detecting step comprises detecting Raman signals.

21. The method of claim 19 wherein the material is selected from the group consisting of chemical and biological warfare agents, chemical and biological contaminants of the environment, explosive agents, controlled substances, chemical and biological agents in manufacturing process streams, and chemical and biological agents in a substrate selected from the group consisting of blood, blood byproducts, urine, saliva, cerebral spinal fluid, tears, semen, uterine secretions, fecal matter, respiratory gases, lung secretions, skin, and aqueous humor of the eye.