Mini-lidar sensor for the remote stand-off sensing of chemical/biological substances and method for sensing same

• US 6,608,677 B1
• Filed: 09/13/2000
• Issued: 08/19/2003
• Est. Priority Date: 11/09/1998
• Status: Expired due to Fees

• Current Assignee: Brookhaven Science Associates, LLC (Government of the United States of America)
• Original Assignee: Brookhaven Science Associates, LLC (Government of the United States of America)
• Inventors: Ray, Mark D., Sedlacek, Arthur J.
• Primary Examiner(s): EVANS, FANNIE L
• Application Number:
  US09/659,202
• Time in Patent Office: 1,070 Days
• Field of Search: 356/301, 356/317, 356/318, 356/417, 250/458.1, 250/459.1, 250/461.1, 250/461.2
• US Class Current: 356/301
• CPC Class Codes: G01N 2021/1793 Remote sensing
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis
• CPC Class Codes: G01N 21/65 Raman scattering

Abstract

A method and apparatus for remote, stand-off, and high efficiency spectroscopic detection of biological and chemical substances. The apparatus including an optical beam transmitter which transmits a beam having an axis of transmission to a target, the beam comprising at least a laser emission. An optical detector having an optical detection path to the target is provided for gathering optical information. The optical detection path has an axis of optical detection. A beam alignment device fixes the transmitter proximal to the detector and directs the beam to the target along the optical detection path such that the axis of transmission is within the optical detection path. Optical information gathered by the optical detector is analyzed by an analyzer which is operatively connected to the detector.

Claims

1. A method for remote, stand-off, in situ spectroscopic detection of a target including a biological substance disposed on a surface comprising the steps of:

providing an optical beam transmitter, and an optical beam detector in a portable instrument to permit transportability of the instrument to a predetermined location;

spacing said transmitter a distance from the surface having the target substance including a biological substance;

transmitting an optical detection beam including at least a laser transmission toward the target substance on the surface;

detecting optical behavior resulting from optical illumination of the target substance on the surface; and

analyzing said optical behavior by spectrally resolving inelastically scattered light resulting from optical illumination of the target substance to determine characteristics of the target substance.

2. The method as defined in claim 1, wherein analyzing said optical behavior includes analyzing the Raman shift in order to determine the characteristics of the target substance.

3. The method as defined in claim 1, wherein said distance between said transmitter and the target substance on the surface is less than 5 meters.

4. The method as defined in claim 1, wherein said distance between said

transmitter and the target substance on the surface is in the range of approximately 2 to 50 meters.

5. The method as defined in claim 1, further comprising the steps of:

providing an optical detector to detect said optical behavior, and positioning said optical detector adjacent said optical beam transmitter.

6. The method as defined in claim 5, further comprising the step of establishing a co-linear optical transmission/detection path between, said optical beam transmitter and said optical detector and the substance.

7. The method as defined in claim 5, wherein the laser transmission has a wavelength of approximately 244 nm.

8. The method as defined in claim 1, further comprising the steps of providing a range finding device and determining the distance from the instrument to the target substance to enhance optical detection of behavior resulting from optical illumination of the target substance on the surface.

9. A method for remote, stand-off, in situ spectroscopic detection of a target biological substance disposed on a surface comprising the steps of:

providing an optical beam transmitter;

spacing said transmitter a distance from the surface having the target biological substance;

transmitting an optical detection beam including at least a laser transmission having a wavelength less than 300 nm toward the target biological substance on the surface;

detecting optical behavior resulting from optical illumination of the target biological substance on the surface; and

analyzing said optical behavior by spectrally resolving inelastically scattered light resulting from optical illumination of the target biological substance to determine characteristics of the target biological substance.

10. A method for remote, stand-off, and high efficiency spectroscopic detection of biological substances, comprising:

establishing a co-linear opticaltransmission/detection path between, a combination optical beam transmitter and spectral analyzer and a target including a biological substance;

transmitting an optical detection beam comprising at least a laser transmission along said path to illuminate said target;

detecting optical behavior resulting from bombardment of the target within said optical detection path; and

analyzing said optical behavior whereby characteristics of the target are detected.

11. The method as defined in claim 10 wherein said co-linear optical transmission/detection path comprises a transmitted optical beam which is co-axial with an optical detection path.

12. The method as defined in claim 10 wherein said establishing comprises fixing a laser beam transmitter sufficiently proximal an optical telescope to direct a laser beam to said target within the optical path of said telescope.

13. The method as defined in claim 12 wherein said laser beam is directed within said optical path by turning said beam at least one time with a beam-directing surface after emission from said laser beam transmitter.

14. The method as defined in claim 13 wherein said turning comprises first reflecting said beam substantially perpendicularly from its path of emission into said optical path, followed by a second reflecting of said beam substantially perpendicular from a beam path resulting from its first reflecting whereby said beam is established co-linearly along said optical transmission/detection path.

15. The method as defined in claim 10 wherein detecting comprises gathering said optical behavior through a telescopic lens and directing said detected optical behavior for analysis.

16. The method as defined in claim 15 wherein said detecting further comprises directing said optical behavior to an optical enhancer before analysis.

17. The method as defined in claim 10, wherein said analyzing comprises converting said optical behavior to spectral information whereby said target characteristics are detected.

18. The method as defined in claim 17, including providing a transducer for converting said spectral information to electrical signals for analysis by a computer.

19. The method as defined in claim 10, wherein analyzing includes spectrally resolving inelastically scattered light resulting from bombardment of the target to determine the composition of the target.

20. The method as defined in claim 10, wherein analyzing includes determining the polarization of elastically scattered light reflected from the target in order to determine the presence of contamination.

21. An apparatus for remote, stand-off, and high efficiency spectroscopic detection of biological and/or chemical substances, comprising:

an optical beam transmitter which transmits a beam having an axis of transmission to a target, said beam comprising at least a laser emission;

an optical detector which gathers optical information and has an optical detection path to the target, said path having an axis of optical detection;

a beam alignment device which fixes said transmitter proximal to said detector and directs said beam to the target along said optical detection path such that said axis of transmission is substantially co-linear with said axis of optical detection; and

an analyzer operatively connected to said detector for receipt of optical information and analysis of same.

22. The apparatus as defined in claim 21, wherein said beam alignment device includes a first beam directing element for directionally altering said beam.

23. The apparatus as defined in claim 22, wherein said beam alignment device includes a second beam directing element for further directionally altering said beam, and wherein said first beam directing element directs said beam emitted from said optical beam transmitter at an angle such that said beam crosses into said optical detection path, and said second beam directing element further directs said beam toward the target.

24. The apparatus as defined in claim 21, wherein said analyzer includes a spectrometer for creating a spectrum by resolving by wavelength scattered light energy and a transducer for converting the spectrum into electrical signals.

25. The apparatus as defined in claim 21, wherein said optical detector includes a telescope having a collecting end and a transmitting end, and the apparatus further includes a filter for rejecting unwanted light energy, said filter being disposed adjacent and operatively connected to the transmission end of said telescope.

26. The apparatus as defined in claim 25, wherein said analyzer includes a spectrum generator for producing a spectrum, said spectrum generator being disposed adjacent and operatively connected to said filter such that light energy passing through said filter may be spectrally resolved by said spectrum generator.

27. The apparatus as defined in claim 26, wherein said analyzer further includes a transducer for converting light energy into electric signals, said transducer being disposed adjacent and operatively connected to said spectrum generator such that transducer converts the spectrum into electrical signals for processing by a computer.

28. The apparatus as defined in claim 21 wherein said laser emission has a wavelength of approximately 244 nm.

29. A portable sensor for determining the composition of a target including a biological and/or chemical substance spaced a distance from the sensor through Raman spectroscopy comprising:

an optical beam transmitter which transmits a beam having an axis of transmission to the target, said beam comprising at least a laser emission;

an optical detector which gathers optical information and has an optical detection path to the target, said path having an axis of optical detection;

a beam alignment device which fixes said transmitter proximal to said detector and directs said beam to the target along said optical detection path such that said axis of transmission is substantially co-linear with said axis of optical detection;

an analyzer operatively connected to said detector for receipt of optical information and analysis of same; and

a rigid platform wherein said optical beam transmitter, said optical detector, said beam alignment device, and said analyzer are secured to said platform such that said sensor may be easily transported to a site and aimed toward a target.

30. A method for remote, stand-off, in situ spectroscopic detection of a target substance disposed on a surface comprising the steps of:

providing an optical beam transmitter, and an optical beam detector in a portable instrument to permit transportability of the instrument to a predetermined location;

spacing said transmitter a distance from the surface having the target substance including a biological substance;

establishing a co-linear optical transmission/detection path between, said optical beam transmitter and said optical detector and the substance

transmitting an optical detection beam including at least a laser transmission toward the target substance on the surface;

detecting optical behavior resulting from optical illumination of the target substance on the surface; and

analyzing said optical behavior by spectrally resolving inelastically scattered light resulting from optical illumination of the target substance to determine characteristics of the target substance.

31. A method for remote, stand-off, and high efficiency spectroscopic detection of solids, liquids and gases, comprising the steps of:

establishing a co-linear optical transmission/detection path between, a combination optical beam transmitter and spectral analyzer and a target wherein said co-linear optical transmission/detection path includes a transmitted optical beam having an axis which is substantially co-linear with an axis of optical detection;

transmitting an optical detection beam including at least a laser transmission along said path to illuminate said target;

detecting optical behavior resulting from bombardment of the target within said optical detection path; and

analyzing said optical behavior whereby characteristics of the target are detected.