Collection probe for use in a Raman spectrometer system and methods of making and using the same

• US 20070127019A1
• Filed: 04/10/2006
• Published: 06/07/2007
• Est. Priority Date: 12/07/2005
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: GE Homeland Protection Incorporated (Safran SA)
• Inventors: Chandrasekaran, Shankar, Maity, Sandip, Banerjee, Ayan, Zribi, Anis, Keimel, Christopher, Tandon, Sheila, Goravar, Shivappa, Tolliver, Todd, Que, Long, Kennerly, Stacey, Hays, David, Claydon, Glenn
• Granted Patent: US 7,411,670 B2
• Time in Patent Office: Days
• US Class Current: 356/301
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0291 Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
• CPC Class Codes: G01J 3/44 Raman spectrometry; Scattering spectrometry ; Fluorescence spectrometry
• CPC Class Codes: G01N 21/65 Raman scattering

Abstract

A photonic crystal based collection probe is provided. The probe includes a photonic crystal configured to guide and condition a beam of Raman scattered photons. Further, the device includes a spectrograph in optical communication with the photonic crystal and configured to receive Raman scattering from the photonic crystal. The device may be employed in a Raman spectrometer system.

Claims

1. A photonic crystal based collection probe, comprising:

a photonic crystal configured to focus Raman scattered photons; and

a spectrograph in optical communication with said photonic crystal and configured to receive Raman scattered photons from said photonic crystal.

2. The photonic crystal based collection probe of claim 1, wherein said spectrograph comprises a micro electromechanical system spectrograph.

3. The photonic crystal based collection probe of claim 2, wherein said spectrograph comprises a tunable Fabry-Perot filter.

4. The photonic crystal based collection probe of claim 1, further comprising a photonic crystal configured to collimate said Raman scattered photons.

5. The photonic crystal based collection probe of claim 1, further comprising a photonic crystal configured to enhance reflectance and finesse of said micro electro mechanical spectrograph.

6. The photonic crystal based collection probe of claim 1, wherein said spectrograph is configured to receive Raman scattering from said photonic crystal.

7. The photonic crystal based collection probe of claim 1, further comprising a filter for Rayleigh scattering separation.

8. The photonic crystal based collection probe of claim 7, further comprising a photonic crystal configured to filter Rayleigh scattered photons from said Raman scattered photons.

9. The photonic crystal based collection probe of claim 7, wherein said filter comprises a fiber Bragg grating device.

10. The photonic crystal based collection probe of claim 9, wherein a grating period of said fiber Bragg grating device is about 330 nanometers.

11. The photonic crystal based collection probe of claim 8, wherein a rejection efficiency of said filter is in a range of from about 80 percent to about 100 percent.

12. The photonic crystal based collection probe of claim 7, wherein said filter comprises a sub-wavelength optical grating.

13. A Raman spectrometer system, comprising:

an electromagnetic radiation source configured to direct electromagnetic radiation on a sample, wherein said sample is configured to interact with said electromagnetic radiation to convert at least a portion of said electromagnetic radiation into Raman scattering and Rayleigh scattering;

a photonic crystal configured to focus said Raman scattering; and

a spectrograph configured to receive said Raman scattering focused from said photonic crystal.

14. The Raman spectrometer system as defined in claim 13, further comprising a fiber Bragg grating device disposed between said photonic crystal and said spectrograph

15. The Raman spectrometer system as defined in claim 13, wherein said fiber Bragg grating device is configured to reject at least a portion of a radiation of predetermined wavelength.

16. The Raman spectrometer system as defined in claim 14, wherein said fiber Bragg grating device is coupled to a heater for altering a pitch of said fiber Bragg grating.

17. The Raman spectrometer system as defined in claim 13, wherein said sample is disposed in a microfluidic channel.

18. The Raman spectrometer system as defined in claim 13, wherein said photonic crystal is disposed in a microfluidic channel.

19. The Raman spectrometer system as defined in claim 13, further comprising a photonic crystal configured to filter Rayleigh scattering from said from said Raman scattering.

20. The Raman spectrometer system as defined in claim 19, wherein said photonic crystal is disposed in a microfluidic device.

21. The Raman spectrometer system as defined in claim 13, further comprising a photonic crystal configured to collimate said Raman scattering.

22. The Raman spectrometer system as defined in claim 13, further comprising a photonic crystal configured to enhance reflectance of photons of said Raman scattering.

23. A method of analyzing a sample in a photonic crystal based collection probe, comprising:

emitting incident electromagnetic radiation to a sample in a chamber to generate a response, wherein the response comprises Raman scattering and Rayleigh scattering;

focusing at least a portion of the Raman scattering through a photonic crystal;

filtering the Rayleigh scattering from the response; and

receiving the portion of the Raman scattering at a spectrograph to generate electrical signals proportional to one or more of a physical, a chemical, or a biological signature of the sample.

24. The method as defined in claim 23, wherein a fiber Bragg grating is employed for said filtering of the Rayleigh scattering.