Dynamic diffractive optical transform

• US 7,009,581 B2
• Filed: 08/09/2004
• Issued: 03/07/2006
• Est. Priority Date: 01/11/1995
• Status: Expired due to Fees

• Current Assignee: William Arthur Birdwell
• Original Assignee: William Arthur Birdwell
• Inventors: Birdwell, William A.
• Primary Examiner(s): Shankar, Vijay
• Application Number:
  US10/915,891
• Publication Number:
  US 20050017925A1
• Time in Patent Office: 575 Days
• Field of Search: 345 7- 10, 345/32, 345/38, 345 48- 55, 345 81- 87, 345/39, 345/59, 349/201, 359/237, 359 36- 39, 359/95, 385 15- 18
• US Class Current: 345/48
• CPC Class Codes: G02F 1/292 by controlled diffraction or phased-array beam steering controlled diffraction for optical switching G02F1/31
• CPC Class Codes: G02F 1/31 Digital deflection, i.e. optical switchingG02F1/33 takes precedence
• CPC Class Codes: G03H 2222/32 Unpolarised light
• CPC Class Codes: G03H 2225/32 Phase only

Abstract

A dynamic diffractive optical transform. An electric field pattern is created across a body of material, the material being characterized in that it has an optical transmission property which varies in response to of an electric potential applied across a portion thereof. The electric field pattern is created such that the resulting profile of the transmission property is an arbitrary shape which produces a desired diffraction pattern that may not be physically realizable in conventional refractive optics or is a Fresnel lens-like construct derived from a refractive optical element. This is done by selectively applying electric potentials to transparent electrode pairs having liquid crystal material therebetween and preferably relatively small proportions in relation to the relevant wavelength of light, so as to create variations in phase delay that are aperiodic, have other than fifty percent spatial duty factor or have multiple levels of phase delay. The transform is embodied in an optical scanner, an adaptive lens, and an optical switch.

Claims

1. A dynamic optical transform, comprising:

a body of material that has an index of refraction whose value varies in response to an electric potential placed across a portion of the material;

a first electrode disposed adjacent the body of material and a second electrode disposed adjacent the body of material, at least one of the first and second electrodes being addressable so as to apply a selected spatial pattern of electric potential to the body of material; and

a processor for receiving arbitrary optical thickness profile information and, in response thereto, producing and applying to said at least one of the first and second electrodes a spatial pattern of electric potential so as to cause the body of material to produce a retardance profile corresponding essentially to a Fresnel lens-like construct of the arbitrary optical thickness profile.

2. The dynamic optical transform of claim 1, wherein the material comprises liquid crystal material.

3. The dynamic optical transform of claim 2, wherein the liquid crystal material is disposed within a liquid crystal cell.

4. The dynamic optical transform of claim 3, wherein at least one of said first and second electrodes is substantially transparent over a selected optical wavelength range.

5. The dynamic optical transform of claim 4, wherein at least one of said first and second electrodes comprises indium tin oxide.

6. The dynamic optical transform of claim 3, wherein said first electrode is disposed on one side of said liquid crystal cell and said second electrode is disposed on the opposing side of said liquid crystal cell.

7. The dynamic optical transform of claim 6, wherein said at least one of the first and second electrodes comprises an array of separately addressable electrode elements.

8. The dynamic optical transform of claim 3, wherein said at least one of the first and second electrodes comprises an array of separately addressable electrode elements.

9. The dynamic optical transform of claim 1, wherein said at least one of the first and second electrodes comprises an array of separately addressable electrode elements.

10. A dynamic optical transform, comprising:

a body of material that has an index of refraction whose value varies in response to an electric potential placed across a portion of the material;

a first electrode disposed adjacent the body of material and a second electrode disposed adjacent the body of material, at least one of the first and second electrodes being addressable so as to apply a selected spatial pattern of electric potential to the body of material; and

a processor for receiving arbitrary optical thickness profile information and, in response thereto, producing and applying to said at least one of the first and second electrodes a spatial pattern of electric potential so as to cause the body of material to produce a quantized index of refraction profile corresponding essentially to the arbitrary optical thickness profile.

11. The dynamic optical transform of claim 10, wherein the material comprises liquid crystal material.

12. The dynamic optical transform of claim 11, wherein the liquid crystal material is disposed within a liquid crystal cell.

13. The dynamic optical transform of claim 12, wherein said first electrode is disposed on one side of said liquid crystal cell and said second electrode is disposed on the opposing side of said liquid crystal cell.

14. The dynamic optical transform of claim 13, wherein the processor is adapted to reduce the arbitrary optical thickness profile to a Fresnel lens-like construct thereof and the quantized retardance profile is based on the Fresnel lens-like construct.

15. The dynamic optical transform of claim 10, wherein at least one of said first and second electrodes is substantially transparent over a selected optical wavelength range.

16. The dynamic optical transform of claim 10, wherein said at least one of the first and second electrodes comprises an array of separately addressable electrode elements.

17. The dynamic optical transform of claim 10, wherein the processor is adapted to reduce the arbitrary optical thickness profile to a Fresnel lens-like construct thereof and the quantized retardance profile is based on the Fresnel lens-like construct.

19. The method of claim 17, wherein said determining includes reducing the arbitrary thickness profile to a Fresnel-like construct thereof whereby the retardance profile is based on the Fresnel-like construct.

18. A method for transforming the wavefront of a light beam, comprising:

directing the light beam through a body of material that has an index of refraction whose value varies in response to an electrical potential placed across a portion of the material;

determining from arbitrary optical thickness profile information a spatial pattern of electric potential that, when applied to at least one face of the body of material, will cause the body of material to produce a retardance profile corresponding essentially to the arbitrary optical thickness profile; and

applying to said at least one face of the body of material the spatial pattern of electric potential so determined.

20. The method of claim 18, wherein said determining of said electric potential comprises determining quantized electric potential values and said applying comprises applying the quantized electric potential values so determined.