Conically scanned holographic lidar telescope

• US 5,255,065 A
• Filed: 03/10/1992
• Issued: 10/19/1993
• Est. Priority Date: 03/10/1992
• Status: Expired due to Term

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Schwemmer, Geary
• Primary Examiner(s): Buczinski, Stephen C.
• Application Number:
  US07/848,885
• Time in Patent Office: 588 Days
• Field of Search: 359/17, 359/18, 356/5
• US Class Current: 356/4.01
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4811 common to transmitter and receiver
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G02B 26/106 having diffraction gratings as scanning elements, e.g. holographic scanners holographic optical elements G02B5/32, holography G03H
• CPC Class Codes: G02B 5/32 Holograms used as optical elements

Abstract

An optical scanning device utilizing a source of optical energy such as laser light backscattered from the earth'"'"'s atmosphere or transmitted outward as in a lidar, a rotating holographic optical element having an axis of rotation perpendicular to the plane of its substrate, and having a stationary focus which may or may not be located on its axis of rotation, with the holographic optical element diffracting the source of optical energy at an angle to its rotation axis enabling a conical scanning area and a motor for supporting and rotating the rotating holographic optical element.

Claims

1. An optical scanning device comprising:

a source of optical energy;

a rotating holographic optical element having a stationary focus, said holographic optical element diffracting said source of optical energy at an angle to said rotation axis so as to define a conical scanning area;

means for supporting and rotating said rotating holographic optical element;

a laser transmitting a beam of light to said rotating holographic optical element, said beam of light diffracted by said rotating holographic optical element and thereby emanating outward from said rotting holographic optical element in a conical manner; and

a small high damage threshold mirror attached to the center of said rotating holographic optical element.

2. The device of claim 1 wherein said stationary focus is located on the axis of rotation of said holographic optical element.

3. The device of claim 1 further comprising a detector means located at said stationary focus of said rotating holographic optical element.

4. The device of claim 3 wherein said source of optical energy comprises laser light backscattered from the earth'"'"'s atmosphere.

5. The device of claim 3 wherein said source of optical energy comprises a natural source of light.

6. The device of claim 5 wherein said natural source of light comprises backscattered solar light.

7. The device of claim 1 further comprising a folding mirror positioned above said rotating holographic optical element.

8. The device of claim 1 further comprising f-matching optics located between said laser and said rotating holographic optical element.

9. The device of claim 2 further comprising secondary optics located on said axis of rotation of said rotating holographic optical element.

10. The device of claim 9 further comprising stationary baffling surrounding said rotating holographic optical element.

11. The device of claim 1 wherein said means for supporting and rotating said rotating holographic optical element comprises a motor means.

12. The device of claim 11 further including an angular momentum compensating flywheel.

13. An optical scanning device comprising:

a source of optical energy;

a plurality of rotating holographic optical elements each having a stationary focus, said plurality of holographic optical elements each diffracting a particular wavelength of said source of optical energy at an angle to said rotation axis so as to define a conical scanning area;

means for supporting said rotating said plurality of rotating holographic optical element;

said plurality of rotating holographic optical elements comprises individual holographic optical elements sandwiched one on top of the other, each transparent to the others wavelengths but diffracting the single wavelength of its design.

14. The device of claim 13 wherein said plurality of rotating holographic optical element comprises multiple holographic optical element produced in the same film.

15. The device of claim 13 wherein said plurality of rotating holographic optical elements occupy separate areas of a substrate in a pie shaped or annular ring fashion.