Dynamic diffractive optical transform

• US 6,774,871 B2
• Filed: 07/30/2002
• Issued: 08/10/2004
• 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:
  US10/209,051
• Publication Number:
  US 20020180682A1
• Time in Patent Office: 742 Days
• Field of Search: 345/7, 345/8, 345/9, 345/10, 345/32, 345/38, 345/48, 345/50, 345/81, 345/82, 345/84, 345/86, 345/87, 349/201, 359/36, 359/39, 359/95, 359/237, 385/15, 385/16, 385/17, 385/18
• 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, the body of material having a first surface and a second surface tat is non-orthogonal to the first surface;

a first, substantially transparent electrode disposed adjacent the first surface and a second electrode disposed adjacent the second surface, 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 the arbitrary optical thickness profile.

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

3. The dynamic optical transform of claim 2, wherein said at least one of the first and second electrodes comprises an array of separately addressable electrode elements.

4. The dynamic optical transform of claim 3, wherein the first electrode comprises indium tin oxide.

5. The dynamic optical transform of claim 1, wherein the processor is adapted to reduce the arbitrary optical thickness profile to a Fresnel-like construct thereof and the retardance profile corresponds to the Fresnel-like construct.

6. The dynamic optical transform of claim 5, wherein the material comprises liquid crystal material.

7. The dynamic optical 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 7, wherein the first electrode comprises indium tin oxide.

9. 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, the body of material having a first surface and a second surface that is non-orthogonal to the first surface;

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.

10. The method of claim 9, wherein said determining includes reducing the arbitrary thickness profile to a Fresnel-like construct thereof whereby the retardance profile corresponds to the Fresnel-like construct.

11. The method of claim 10, further comprising providing as the arbitrary thickness profile the profile of a wedge.

12. The method of claim 10, further comprising providing as the arbitrary thickness profile the profile of a lens having a spherical surface.

13. The method of claim 10, comprising providing as the arbitrary thickness profile the profile of a lens having an aspherical surface.