System and method for combined Raman and LIBS detection

• US 8,687,177 B2
• Filed: 10/06/2010
• Issued: 04/01/2014
• Est. Priority Date: 01/23/2007
• Status: Active Grant

• Current Assignee: Chemimage Corporation
• Original Assignee: Chemimage Corporation
• Inventors: Beckstead, Jeff, Nelson, Matthew, Treado, Patrick
• Primary Examiner(s): Toatley, Gregory J
• Assistant Examiner(s): ALLI, IYABO
• Application Number:
  US12/899,055
• Publication Number:
  US 20110085165A1
• Time in Patent Office: 1,273 Days
• Field of Search: 356/73, 356/73.1, 356/445, 356/446, 356/301, 356/451
• US Class Current: 356/73.1
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/0272 Handheld
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/28 Investigating the spectrum using colour filters G01J3/51
• CPC Class Codes: G01J 3/36 Investigating two or more bands of a spectrum by separate detectors
• CPC Class Codes: G01J 3/44 Raman spectrometry; Scattering spectrometry ; Fluorescence spectrometry
• CPC Class Codes: G01J 3/443 Emission spectrometry
• CPC Class Codes: G01N 21/65 Raman scattering
• CPC Class Codes: G01N 21/718 Laser microanalysis, i.e. with formation of sample plasma
• CPC Class Codes: G01N 2201/0221 Portable; cableless; compact; hand-held
• CPC Class Codes: G01N 2201/06113 Coherent sources; lasers
• CPC Class Codes: G01N 2201/0833 Fibre array at detector, resolving
• CPC Class Codes: G01N 2201/0846 Fibre interface with sample, e.g. for spatial resolution

Abstract

A system and method for detection and identification of unknown samples using a combination of Raman and LIBS detection techniques. A first region of a sample and a second region of a sample are illuminated using structured illumination to thereby generate a first plurality of interacted photons and a second plurality of interacted photons. This first plurality and second plurality of interacted photons may be passed through a fiber array spectral translator device. Said first plurality of interacted photons are assessed using Raman spectroscopy to thereby generate a Raman data set. Said second plurality of interacted photons are assessed using LIBS spectroscopy to thereby generate LIBS data set. These data sets may be analyzed to identify the sample. These data sets may also be fused for further analysis.

Claims

1. A system comprising:

an illumination source, wherein said illumination source is configured to illuminate at least one of;

a first region of a sample to thereby generate a first plurality of interacted photons and a second region of said sample to thereby generate a second plurality of interacted photons;

a fiber array spectral translator device, wherein said device comprises a two-dimensional array of optical fibers drawn in into a one-dimensional fiber stack so as to effectively convert a two-dimensional field of view into a curvilinear field of view and, a Raman spectrometer wherein said Raman spectrometer is configured so as to effectively separate said first plurality of interacted photons into a first plurality of wavelength bands;

a LIBS spectrometer wherein said LIBS spectrometer is configured so as to effectively separate said second plurality of interacted photons into a second plurality of wavelength bands;

a Raman detector to thereby generate a Raman data set representative of said first region; and

a LIBS detector to thereby generate a LIBS data set representative of said second region of said sample.

2. The system of claim 1 wherein said first region and said second region comprise non-overlapping regions of said sample.

3. The system of claim 1 wherein at least one fiber of said fiber array spectral translator device is associated with said first region and wherein at least one fiber of said fiber array spectral translator device is associated with said second region.

4. The system of claim 3 wherein said fiber associated with said first region is configured so as to transmit said first plurality of interacted photons to said Raman spectrometer.

5. The system of claim 3 wherein said fiber associated with said second region is configured so as to transmit said second plurality of interacted photons to said LIBS spectrometer.

6. The system of claim 1 wherein said illumination source is configured so as to illuminate said first region and said second region simultaneously.

7. The system of claim 1 wherein said illumination source is configured for structured illumination.

8. The system of claim 1 wherein said illumination source is configured so as to illuminate said first region with a first excitation wavelength and said second region with a second excitation wavelength.

9. The system of claim 1 further comprising a frequency doubling crystal to achieve multi-wavelength illumination using one illumination source.

10. The system of claim 1 further comprising a means for enabling at least one of Raman time-gated detection and LIBS time-gated detection.

11. A method comprising:

illuminating a first region of a sample to thereby generate a first plurality of interacted photons;

illuminating a second region of said sample to thereby generate a second plurality of interacted photons;

passing said first plurality of interacted photons and said second plurality of interacted photons through a fiber array spectral translator device;

detecting said first plurality of interacted photons using Raman gated detection to thereby generate at least one Raman data set representative of said first region of said sample; and

detecting said second plurality of interacted photons using LIBS gated detection to thereby generate at least one LIBS data set representative of said second region of said sample.

12. The method of claim 11 further comprising:

receiving said first plurality of interacted photons and said second plurality of interacted photons at a two-dimensional end of said fiber array spectral translator device, wherein said device comprises;

a two-dimensional array of optical fibers drawn into a one-dimensional fiber stack so as to effectively convert a two-dimensional field of view into a curvilinear field of view, at least one of said fibers is associated with said first region of said sample, and at least one of said fibers is associated with said second region of said sample.

13. The method of claim 12 further comprising:

delivering said first plurality of interacted photons to a Raman grating array via said fiber associated with said first region of said sample, and delivering said second plurality'"'"' of interacted photons to a LIBS grating array via said fiber associated with said second region of said sample.

14. The method of claim 13 wherein said Raman grating array and said LIBS grating array are incorporated into one spectrometer.

15. The method of claim 13 wherein said Raman grating array is incorporated into a Raman spectrometer and said LIES grating array are incorporated into a LIBS spectrometer.

16. The method of claim 11 wherein at least one of said first region and said second region are illuminated using least one of:

continuous wave laser excitation, pulsed laser excitation, and combinations thereof.

17. The method of claim 11 wherein said first region of said sample is illuminated using a first wavelength and said second region of said sample is illuminated using a second wavelength.

18. The method of claim 11 wherein said Raman gated detection comprises configuring data acquisition to occur during a predetermined period of time.

19. The method of claim 11 wherein said predetermined period of time is equal to a Raman emission time.

20. The method of claim 11 wherein said LIES gated detection comprises configuring data acquisition to occur during a predetermined period of time.

21. The method of claim 20 wherein said predetermined period of time comprises a LIBS emission time.

22. The method of claim 11 wherein said illumination of said first region and said second region of performed sequentially.

23. The method of claim 11 wherein said detection of said first plurality of interacted photons and said second plurality of interacted photons is performed simultaneously.

24. The method of claim 11 further comprising analyzing at least one of said Raman data set and said LIBS data set to thereby identify said sample as comprising at least one of:

an explosive threat material, a biological threat material, a chemical threat material, a non-threat material, a material associated with threat materials, and combinations thereof.

25. The method of claim 24 wherein said analysis comprises comparing at least one of said Raman data set and said LIBS data set with one or more reference data sets wherein each reference data set is associated with a known sample.

26. The method of claim 25 wherein said comparison comprises applying at least one chemometric technique to at least one of said Raman data set and said LIBS data set.

27. The method of claim 11 further comprising fusing said Raman data set and said LIBS data set to thereby generate a fused data set.

28. The method of claim 17 further comprising analyzing said fused data set to thereby identify said sample as comprising at least one of:

an explosive threat material, a biological threat material, a chemical threat material, a non-threat material, a material associated with threat materials, and combinations thereof.

29. The method of claim 28 wherein said analyzing comprises comparing said fused data set with a reference data set wherein said reference data set corresponds to a known sample.

30. The method of claim 29 wherein said comparison is achieved using at least one chemometric technique.

31. The method of claim 11 further comprising switching between acquisition of said Raman data set and acquisition of said LIBS dataset.