Multimode waveguide holograms capable of using non-coherent light

• US 5,295,208 A
• Filed: 02/26/1992
• Issued: 03/15/1994
• Est. Priority Date: 02/26/1992
• Status: Expired due to Fees

• Current Assignee: University of Alabama (University of Alabama System)
• Original Assignee: University of Alabama (University of Alabama System)
• Inventors: Huang, Qiang, Caulfield, H. John, Morozov, Valentin, Putilin, Andrei
• Primary Examiner(s): Lee, John D.
• Assistant Examiner(s): Heartney, Phan Thi
• Application Number:
  US07/841,576
• Time in Patent Office: 748 Days
• Field of Search: 385/36, 385/37, 385/41, 385/42, 385/27, 385/129, 359/34
• US Class Current: 385/27
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: G02B 6/43 Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections
• CPC Class Codes: G03H 1/0408 Total internal reflection [TIR] holograms, e.g. edge lit or substrate mode holograms
• CPC Class Codes: G03H 2001/2226 Edge lit holograms TIR recording G03H1/0408

Abstract

A multimode waveguide having a small thickness has light coupled to the side of the waveguide in order to provide a multimode operation of the waveguide for providing a continuous pattern of totally internally reflected light which is utilized to reconstruct holographic images from a holographic emulsion placed on a surface of the waveguide. This waveguide structure for reconstructuring a hologram has the capability of providing highly efficient hologram reconstruction while using ordinary light sources and is able to use beam diameters greater than the thickness of the waveguide.

Claims

1. A multitude waveguide structure comprising:

a dielectric waveguide for supporting multimode propagation of light wherein said waveguide has two main side surfaces defining a thickness therebetween and a length substantially greater than width with the ends of the lengthwise each extent of the waveguide being defined by a respective edge;

input coupling means for coupling a light beam of a frequency λ

into one of said main side surfaces in the vicinity of a first one of said edges to thereby provide a spatially continuous pattern of totally internally reflected light within said waveguide, wherein said thickness is greater than said frequency,

further including an holographic emulsion placed on said one surface in the vicinity of said second edge wherein said holographic emulsion contains a previously recorded holographic image.

2. The waveguide according to claim 1, wherein said input coupling means is a grating.

3. The waveguide according to claim 1, wherein said input coupling means couples a point source of light to said one side surface.

4. The waveguide according to claim 1, wherein said input coupling means couples white light to said one side surface.

5. The waveguide according to claim 1, wherein said previously recorded holographic image is reconstructed by means of the interaction of said continuous pattern of totally internally reflected light said holographic emulsion in such a way that a portion of the light is diffracted for reconstruction of the image with the remainder of the light reflected from the surface containing said holographic emulsion.

6. The waveguide according to claim 1, wherein the thickness of said waveguide is less than the width of said beam of light on said one surface.

7. The multimode waveguide according to claim 1, further including a means placed on said one surface near said second edge which interacts with said continuous pattern of reflected light by providing multiple utilizations of said reflected light.

8. The waveguide according to claim 1, wherein said input coupling means is an optical fiber means.

9. The waveguide according to claim 1, wherein said input coupling means is a prism.

10. The waveguide according to claim 1, wherein said light beam is a beam of non-coherent light.

11. The waveguide of claim 10, wherein said non-coherent light is white light.