Very fast time resolved imaging in multiparameter measurement space

• US 7,227,116 B2
• Filed: 04/26/2001
• Issued: 06/05/2007
• Est. Priority Date: 04/26/2000
• Status: Expired due to Term

• Current Assignee: Arete Associates
• Original Assignee: Arete Associates
• Inventors: Gleckler, Anthony D.
• Primary Examiner(s): LE, QUE TAN
• Application Number:
  US10/258,917
• Publication Number:
  US 20040031906A1
• Time in Patent Office: 2,231 Days
• Field of Search: 250/208.1, 250/559.4, 250/214.VT
• US Class Current: 250/208.1
• CPC Class Codes: G01J 11/00 Measuring the characteristics of individual optical pulses or of optical pulse trains
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/0229 using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 3/0256 Compact construction
• CPC Class Codes: G01J 3/0294 Multi-channel spectroscopy
• CPC Class Codes: G01J 3/04 Slit arrangements slit adjustment
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G01J 3/2823 Imaging spectrometer
• CPC Class Codes: G01J 3/2889 Rapid scan spectrometers; Time resolved spectrometry
• CPC Class Codes: G01J 3/36 Investigating two or more bands of a spectrum by separate detectors
• CPC Class Codes: G01J 3/447 Polarisation spectrometry
• CPC Class Codes: G01J 4/00 Measuring polarisation of light
• CPC Class Codes: G01J 9/00 Measuring optical phase difference devices or arrangements for controlling the phase of light beams G02F1/01; Determining degree of coherence; Measuring optical wavelength spectrometry G01J3/00
• CPC Class Codes: G01N 2021/1793 Remote sensing
• CPC Class Codes: G01N 2021/6417 Spectrofluorimetric devices
• CPC Class Codes: G01N 2021/6423 Spectral mapping, video display
• CPC Class Codes: G01N 21/21 Polarisation-affecting properties G01N21/19 takes precedence
• CPC Class Codes: G01N 21/31 Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry G01N21/72 takes precedence
• CPC Class Codes: G01N 21/6408 with measurement of decay time, time resolved fluorescence
• CPC Class Codes: G01N 21/6456 : Spatial resolved fluorescence measurements; Imaging
• CPC Class Codes: G01S 17/89 : for mapping or imaging
• CPC Class Codes: G01S 7/481 : Constructional features, e.g. arrangements of optical elements
• CPC Class Codes: G01S 7/4817 : relating to scanning
• CPC Class Codes: G04F 13/02 : using optical means
• CPC Class Codes: G04F 13/026 : Measuring duration of ultra-short light pulses, e.g. in the pico-second range; particular detecting devices therefor photometry, radiation pyrometry G01J1/00, G01J5/00; non-linear optics G02F1/35
• CPC Class Codes: H01J 43/00 : Secondary-emission tubes; Electron-multiplier tubes dynamic electron-multiplier tubes H01J25/76

Abstract

Plural electronic or optical images are provided in a streak optical system, as for instance by use of plural slits instead of the conventional single slit, to obtain a third, fourth, etc. dimension—rather than only the conventional two, namely range or time and azimuth. Such additional dimension or dimensions are thereby incorporated into the optical information that is to be streaked and thereby time resolved. The added dimensions may take any of an extremely broad range of forms, including wave-length, polarization state, or one or more spatial dimensions—or indeed virtually any optical parameter that can be impressed upon a probe beam. Resulting capabilities remarkably include several new forms of lidar spectroscopy, fluorescence analysis, polarimetry, spectropolarimetry, and combinations of these, as well as a gigahertz wavefront sensor.

Claims

1. A streak lidar imaging system for measurements of a medium with any objects therein;

said system comprising;

a light source for emitting at least one beam into such medium;

an imaging device for receiving light reflected from such medium and forming plural images, arrayed along a streak direction, of the reflected light;

wherein the imaging device comprises plural slits for selecting particular bands of the plural images respectively; and

a device for displacing all the plural images along the streak direction.

2. The system of claim 1, wherein:

the imaging device comprises an optical device;

the plural images are optical images; and

the displacing device comprises a module for displacing the plural optical images.

3. The system of claim 2, wherein:

the displacing device comprises an electromechanical device.

4. The system of claim 3, wherein:

the electromechanical device comprises at least one scanning microelectromechanical mirror.

5. The system of claim 3, wherein:

the electromechanical device comprises an array of scanning microelectromechanical mirrors.

6. The system of claim 2, wherein:

the displacing device comprises an electrooptical device.

7. The system of claim 1, wherein:

the imaging device comprises an electronic device;

the plural images are electronic images; and

the displacing device comprises a module for displacing the plural electronic images.

8. The system of claim 7, wherein:

the displacing device comprises electronic deflection plates.

9. The system of claim 7, wherein the imaging device comprises:

an optical front end that forms a single optical image of the reflected light; and

an electronic stage receiving the single optical image and forming therefrom the plural electronic images.

10. The system of claim 7, wherein the imaging device comprises:

an optical front end that forms plural optical images of the reflected light; and

an electronic stage receiving the plural optical images and forming therefrom the plural electronic images.

11. The system of claim 1:

wherein the displacing device forms from each of the plural images a respective streak image;

whereby the displacing device forms, from the plural images considered in the aggregate, a corresponding array of plural streak images; and

further comprising a device for receiving the array of plural streak images and in response forming a corresponding composite signal.

12. The system of claim 1, wherein:

the plural slits operate on the images in optical form.

13. The system of claim 1, wherein:

the plural slits operate on the images in electronic form.

14. The system of claim 1, wherein:

the imaging device comprises a module for forming substantially a continuum of images of the reflected beam; and

each of the plural slits selects a particular image band from the continuum.

15. The system of claim 1, wherein:

the light source comprises an optical module for emitting at least one thin, fan-shaped beam into such medium;

the imaging device comprises an optical module for receiving at least one thin, fan-shaped beam reflected from such medium; and

at least one of the optical modules comprises an optical unit for orienting a thin dimension of the reflected beam along the streak direction.

16. The system of claim 1, wherein:

the imaging device comprises an optical module for forming the plural images as images of the at least one reflected beam at discrete optical wavelengths, respectively.

17. The system of claim 1, wherein:

the imaging device comprises an optical module for forming the plural images as images of the at least one reflected beam in different polarization states, respectively.

18. The system of claim 1, wherein:

the imaging device comprises an optical device for forming the plural images from different angular sectors, respectively, of the at least one reflected beam.

19. The system of claim 18, wherein:

the imaging device further comprises an optical device for rearranging image elements in each angular sector to form a single line image for that sector.

20. The system of claim 19, wherein:

the optical device comprises remapping optics.

21. The system of claim 20, wherein:

the remapping optics comprise a fiber-optic or laminar-optic module.

22. The system of claim 20, wherein:

the remapping optics comprise a lenslet array.

23. The system of claim 1, wherein:

the light source comprises means for emitting plural beams into such medium; and

the imaging device comprises;

means for receiving plural beams of the reflected light from such medium, and

an optical device for forming the plural images from, respectively, the plural reflected beams.

24. The system of claim 1, wherein:

the light source comprises an emitter for emitting light in a wavelength region at or near 1½

microns.

25. The system of claim 24, wherein:

the imaging device comprises an upconverter for generating light at or near the visible wavelength region in response to the light at or near 1½

microns.

26. The system of claim 25, wherein:

the upconverter comprises ETIR material.

27. The system of claim 1, wherein:

the light source comprises means for emitting the at least one beam into such medium that is selected from the group consisting of;

a generally clear fluid above a generally hard surface;

a turbid medium, including but not limited to ocean water, wastewater, fog, clouds, smoke or other particulate suspensions;

a diffuse medium, including but not limited to foliage at least partially obscuring a landscape.

28. A lidar imaging system for optical measurements of a medium with any objects therein;

said system comprising;

a light source for emitting at least one light pulse into such medium; and

means for receiving the at least one light pulse reflected from such medium and for forming from each reflected pulse a set of plural substantially simultaneous two-dimensional output images, each image representing reflected energy in two dimensions.

29. The system of claim 28:

wherein the light source comprises means for emitting a series of light pulses into such medium, each of the pulses in the series generating a corresponding such set of plural substantially simultaneous two-dimensional images;

whereby the receiving means generate a series of plural corresponding two-dimensional image sets; and

further comprising means for storing the series of corresponding two-dimensional image sets.

30. The system of claim 28, wherein:

the receiving means comprise means for allocating image elements, in each image of the set, as among (1) azimuth, (2) range or time, and (3) an extrinsic measurement dimension.

31. The system of claim 30, wherein:

the extrinsic measurement dimension is wavelength.

32. The system of claim 30, wherein:

the extrinsic measurement dimension is polarization state.

33. The system of claim 30, wherein:

the extrinsic measurement dimension is a spatial selection.

34. The system of claim 28, wherein:

the receiving means comprise means for causing the images in the set to be substantially contiguous.

35. The system of claim 28, wherein:

the receiving means comprise means for receiving the reflected light pulse as a beam with a cross-section that has an aspect ratio on the order of 1;

1.

36. The system of claim 35, wherein:

the light source comprises means for emitting the at least one light pulse as a beam with a cross-section that has an aspect ratio on the order of 1;

1.

37. The system of claim 28, wherein:

the receiving means comprise means for forming the images in such a way that the two dimensions are range/time and output-image azimuth, for a particular extrinsic dimension that corresponds to each output image respectively.

38. The system of claim 28, wherein:

the light source comprises means for emitting the at least one beam into such medium that is a generally clear fluid above a generally hard surface.

39. The system of claim 28, wherein:

the light source comprises means for emitting the at least one beam into such medium that is a turbid medium, including but not limited to ocean water, wastewater, fog, clouds, smoke or other particulate suspensions.

40. The system of claim 28, wherein:

the light source comprises means for emitting the at least one beam into such medium that is a diffuse medium, including but not limited to foliage at least partially obscuring a landscape.

41. A streak lidar imaging system for making measurements of a medium with any objects therein;

said system comprising;

a light source for emitting into such medium a beam in an eye-safe wavelength range;

an imaging device for receiving light reflected from such medium and forming an image of the reflected light;

an upconverter for generating light at or near the visible wavelength region in response to the reflected light in an eye-safe wavelength range; and

a device for displacing the image along a streak direction.

42. The system of claim 41, wherein:

the upconverter is positioned in the system after the displacing device.

43. The system of claim 41, wherein:

the upconverter comprises ETIR material.

44. The system of claim 41, wherein:

the displacing device is positioned in the system after the upconverter.

45. A streak lidar imaging system for making measurements of a medium with any objects therein;

said system comprising;

a light source for emitting into such medium a beam in a substantially eye-safe wavelencrth range;

an imaging device for receiving light reflected from such medium and forming an image of the reflected light;

an upconverter for generating light at or near the visible wavelength region in response to the reflected light in a substantially eye-safe wavelength range; and

a device for displacing the image alone a streak direction;

wherein;

the light source emits said beam in a wavelength range at substantially 1½

microns.

46. A streak lidar imaging system comprising:

a light source for emitting a beam;

an imaging device for receiving light originating from the source and for forming an image of the received light;

at least one microelectromechanical-system mirror for displacing the image along a streak direction; and

an image-responsive element for receiving and responding to the displaced image.

47. The system of claim 46, wherein:

the at least one mirror comprises an array of multiple microelectromechanical-system mirrors.

48. The system of claim 46, for use with an optical medium and wherein:

the light source comprises means for emitting the beam into such medium; and

the imaging device comprises means for receiving light reflected from such medium and forming an image of the reflected light.

49. The system of claim 46, wherein:

the light source comprises a resonant device; and

the imaging device comprises means for causing imperfections in resonance of the resonant device to modulate the image.

50. The system of claim 49, particularly for use with a resonant device that comprises a laser;

and wherein;

the imaging device comprises means for causing imperfections in optical wavefronts from the laser to modulate the image.

51. The system of claim 50, wherein:

the causing means comprise means for deflecting elements of said beam in response to local imperfections in said wavefronts.

52. The system of claim 51, wherein:

the deflecting means comprise at least one lenslet array.