HIGH-SPEED, RUGGED, TIME-RESOLVED, RAMAN SPECTROMETER FOR SENSING MULTIPLE COMPONENTS OF A SAMPLE AND FOR DIAGNOSTICS OF PATHOLOGICAL SKIN CONDITIONS SUCH AS CANCER

• US 20100027002A1
• Filed: 08/31/2009
• Published: 02/04/2010
• Est. Priority Date: 06/12/2006
• Status: Active Grant

• Current Assignee: Ricardo Claps
• Original Assignee: Ricardo Claps
• Inventors: CLAPS, Ricardo
• Granted Patent: US 7,944,555 B2
• Time in Patent Office: Days
• US Class Current: 356/301
• CPC Class Codes: G01J 2003/123 Indexed discrete filters
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/0227 using notch filters
• CPC Class Codes: G01J 3/1895 using fiber Bragg gratings or gratings integrated in a waveguide
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• CPC Class Codes: G01J 3/2889 Rapid scan spectrometers; Time resolved spectrometry
• CPC Class Codes: G01J 3/32 Investigating bands of a spectrum in sequence by a single detector
• CPC Class Codes: G01J 3/44 Raman spectrometry; Scattering spectrometry ; Fluorescence spectrometry
• CPC Class Codes: G01N 21/65 Raman scattering

Abstract

A new architecture for implementing a time-resolved Raman spectrometer is 2-3 orders of magnitude faster than current systems. In one embodiment, the invention employs a rotating optical switch to time multiplex an input signal through multiple band-pass filters and into a single optical detector which is electrically activated only when the filtered input light pulse is about to impact it.

Time-multiplexing the input signal through multiple optical filters and time-sequencing the optical detector enables the device to detect and analyze 2-3 orders of magnitude faster than current designs. In one embodiment, the system may be employed for the diagnostics of a pathological condition of skin tissue in patients, such as malignant melanoma or other types of skin cancers and abnormal conditions.

Claims

1. A Raman spectroscopy system comprising:

a plurality of light transmission channels;

a time-division multiplexing device for distributing Stokes radiation scattered from a sample as a result of light impinging on said sample to each of said plurality of light transmission channels; and

a light detector for detecting the Stokes radiation passed by each of said transmission channels, further wherein each of said transmission channels comprises a filter to select a specific wavelength range for each channel.

2. The system of claim 1, further comprising:

a synchronizing circuit for turning on said detector only when Stokes radiation from said multiplexing device is expected at said detector and otherwise leaving off said detector.

3. The system of claim 1 further comprising:

analysis means for processing a signal from said detector when said detector is impacted by Stokes radiation to detect selected information in said Stokes radiation.

4. A Raman spectroscopy system comprising:

a plurality of light sources each light source producing radiation to be directed at a sample;

a time division multiplexing device for transmitting radiation from each light source to a sample such that at least a portion of that radiation is scattered from the sample;

a detector responsive to at least a portion of said scattered radiation for producing a signal representing information in said sample; and

a synchronizing circuit for turning on the detector at the times that radiation scattered from the sample is expected at the detector.

5. The system as in claim 4 further comprising:

a light transmission channel for transmitting at least a portion of the radiation scattered from the sample to said detector; and

a narrow pass-band filter in series with said light transmission channel to pass at least a portion of the radiation scattered from the sample.

6. The system of claim 4 further comprising:

analysis means connected to said detector for processing each signal from said detector to detect selected information in each signal.

7. The system of claim 4 wherein said synchronizing circuit synchronizes the turning on of said detector with the arrival at said detector of at least a portion of said radiation scattered from said sample.

8. The system of claim 4 wherein said synchronizing circuit synchronizes the turning on of said detector with the arrival at said detector of at least a portion of said radiation scattered from said sample so as to maximize the sensitivity of the system.

9. The system of claim 4 wherein said synchronizing circuit synchronizes the turning on of said detector with the arrival at said detector of at least a portion of said radiation scattered from said sample so as to reduce the dark count and noise level present at said analysis means.

10. The system as in claim 4 wherein said plurality of light sources comprise a plurality of lasers, each laser operating at a different wavelength from the other lasers.

11. The system as in claim 4 wherein said plurality of light sources comprise emission lamps.

12. The system as in claim 11 further comprising:

a plurality of narrow band-pass filters arranged to allow only a portion of the light from each emission lamp to reach said sample.

13. The system of claim 11 wherein each emission lamp comprises a lamp containing mercury, xenon, neon or other gas capable of emitting radiation.

14. A Raman spectroscopy system comprising:

a plurality of light transmission channels;

a time-division multiplexing device for distributing radiation scattered from a sample as a result of light impinging on said sample to each of said plurality of light transmission channels; and

a light detector for detecting the radiation passed by each of said transmission channels.

15. The system of claim 14, further comprising:

a synchronizing circuit for turning on said detector only when radiation from said multiplexing device is expected at said detector and otherwise leaving off said detector.

16. The system of claim 14 further comprising:

analysis means for processing a signal from said detector when said detector is impacted by radiation to detect selected information in said radiation.

17. A method of implementing a Raman spectroscopy procedure which comprises:

causing light to impinge on a sample thereby to scatter

said light from said sample to produce Stokes radiation;

distributing the Stokes radiation to each of a plurality of

transmission channels so as to cause the Stokes radiation transmitted by said plurality of transmission channels to arrive in sequence at an optical detector; and

synchronizing the turning on of said optical detector with

the arrival at said optical detector of the Stokes radiation from each of said plurality of transmission channels.

18. The method of claim 17 wherein synchronizing the turning on of said optical detector causes said optical detector to generate a signal uniquely related to the characteristics of the Stokes radiation arriving at said optical detector while the optical detector is turned on.

19. The method of claim 17 further comprising:

analyzing each signal from said optical detector to determine the characteristics of the component of said sample being measured by the Stokes radiation which generated said signal.

20. The method of claim 17 further comprising:

analyzing each signal from said optical detector using a discrete principle component analysis procedure to detect an analyte in said sample.

21. The method of claim 20 wherein analyzing each signal from said optical detector further comprises analyzing each signal from said optical detector to detect two or more discrete multiple analytes in said sample.

22. The method of claim 17 wherein the distributing of the Stokes radiation to each of a plurality of transmission channels is done by a time-division multiplexing device such that two or more analytes in said sample can be detected in one cycle of rotation of said multiplexing device.

23. A method of implementing Raman spectroscopy comprising:

producing from a plurality of light sources radiation to be directed at a sample;

transmitting radiation from each light source in time sequence to a sample such that at least a portion of the radiation from each light source is scattered in time sequence from the sample;

transmitting a portion of the radiation from each light source scattered from the sample to a detector;

producing a signal at said detector representing information in said sample; and

synchronizing the turning on of the detector with the arrival at the detector of at least a portion of the radiation from each light source scattered from the sample.

24. The method of claim 23 wherein transmitting radiation from each light source in time sequence to a sample comprises time multiplexing the radiation from said plurality of light sources.

25. A method of implementing a Raman spectroscopy procedure which comprises:

causing light to impinge on a sample thereby to scatter said light from said sample to produce radiation;

distributing the radiation to each of a plurality of transmission channels so as to cause the radiation transmitted by said plurality of transmission channels to arrive in sequence at an optical detector; and

synchronizing the turning on of said optical detector with the arrival at said optical detector of the radiation from each of said plurality of transmission channels.

26. The method of claim 25 wherein synchronizing the turning on of said optical detector causes said optical detector to generate a signal uniquely related to the characteristics of the radiation arriving at said optical detector while the optical detector is turned on.

27. The method of claim 25 further comprising:

analyzing each signal from said optical detector to determine the characteristics of the component of said sample being measured by the radiation which generated said signal.

28. The method of claim 27 further comprising:

analyzing each signal from said optical detector using a discrete principle component analysis procedure to detect an analyte in said sample.

29. The method of claim 28 wherein analyzing each signal from said optical detector further comprises analyzing each signal from said optical detector to detect two or more discrete multiple analytes in said sample.

30. The method of claim 27 wherein the distributing of the radiation to each of a plurality of transmission channels is done by a time-division multiplexing device such that two or more analytes in said sample can be detected in one cycle of rotation of said multiplexing device.