Surface relief volume reflective diffractive structure

• US 9,158,046 B2
• Filed: 08/14/2012
• Issued: 10/13/2015
• Est. Priority Date: 02/14/2007
• Status: Active Grant

• Current Assignee: Kavlico Corporation (Sensata Technologies Holding Plc)
• Original Assignee: Kavlico Corporation (Sensata Technologies Holding Plc)
• Inventors: Cowan, James J.
• Primary Examiner(s): Lavarias, Arnel C
• Application Number:
  US13/559,927
• Publication Number:
  US 20120300272A1
• Time in Patent Office: 1,155 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G02B 5/1814 structurally combined with one or more further optical elements, e.g. lenses, mirrors, prisms or other diffraction gratings G02B5/189 takes precedence
• CPC Class Codes: G02B 5/1861 Reflection gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials G02B5/1809, G02B5/1828, G02B5/1833, G02B5/1838 and G02B5/1847 take precedence
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: G03H 1/0244 Surface relief holograms replicating hologram without interference recording G03H1/0276
• CPC Class Codes: G03H 1/0248 Volume holograms
• CPC Class Codes: G03H 1/04 Processes or apparatus for producing holograms G03H1/26 takes precedence
• CPC Class Codes: G03H 1/0402 Recording geometries or arrangements G03H1/0443, G03H1/0476, G03H1/16 take precedence
• CPC Class Codes: G03H 1/041 Optical element in the object space affecting the object beam, not otherwise provided for
• CPC Class Codes: G03H 1/2205 using downstream optical component
• CPC Class Codes: G03H 1/2249 Holobject properties
• CPC Class Codes: G03H 1/26 Processes or apparatus specially adapted to produce multiple sub- holograms or to obtain images from them, e.g. multicolour technique
• CPC Class Codes: G03H 2001/0417 for recording single beam Lippmann hologram wherein the object is illuminated by reference beam passing through the recording material
• CPC Class Codes: G03H 2001/0419 for recording combined transmission and reflection holograms
• CPC Class Codes: G03H 2001/0473 Particular illumination angle between object or reference beams and hologram
• CPC Class Codes: G03H 2001/2635 Mixed volume and surface relief holograms
• CPC Class Codes: G03H 2210/63 Environment affecting the recording, e.g. underwater G03H2001/0432 takes precedence
• CPC Class Codes: G03H 2222/31 Polarised light
• CPC Class Codes: G03H 2223/18 Prism
• CPC Class Codes: G03H 2223/25 Index matching material
• CPC Class Codes: G03H 5/00 Holographic processes or apparatus using particles or using waves other than those covered by groups G03H1/00 or G03H3/00 for obtaining holograms; Processes or apparatus for obtaining an optical image from them G03H1/22 takes precedence; construction of electron microscopes H01J37/26; investigating or analysing materials by the use of microwaves G01N22/00, by the use of particles wave or X-rays G01N23/00, G21K7/00

Abstract

A surface relief structure includes a recording medium configured to be structurally modified when exposed to interfering and non-interfering portions of radiation beams, the structurally modified recording medium including, when viewed in a two-dimensional cross-section along one of the axes of the recording medium a plurality of equally spaced steps of fine-sized periodicity superimposed upon a plurality of deep depressions of substantially coarse-sized periodicity. The structurally modified recording medium is configured to produce in reflection single and multiple colors in a broad spectral range when illuminated by a source of light.

Claims

1. A method for recording a holographic image of an object, the method comprising:

providing a recording medium configured to record a holographic image, the recording medium having two principal surfaces;

placing the object proximate one of the two principal surfaces of the recording medium; and

directing radiation beams at another surface of the two principal surfaces of the recording medium at an angle with respect to a normal to the other of the two principal surfaces of the recording medium such that a resultant radiation beam reflected from the object interferes with a resultant first reference beam progressing in a direction that is at least partly similar to a progression direction of the resultant radiation beam reflected from the object, both beams being separated by a small angle such that a first interference fringe structure is formed in the recording medium that is skewed with respect to any of the two principal surfaces of the recording medium, and such that a resultant second reference beam progresses in a general direction that is at least partly opposite to the progression direction of the resultant radiation beam reflected from the object such that a second, fine-sized, set of interference fringes is formed in the recording medium, the second set of interference fringes being skewed with respect to the any of the two principal surfaces of the recording medium.

2. The method of claim 1 wherein the skewed first interference fringe structure includes at least one of:

an inclined first interference fringe structure and a non-symmetric interference fringe structure.

3. The method of claim 1 wherein providing the recording medium comprises:

providing a photoresist medium.

4. The method of claim 1 wherein placing the object comprises:

encapsulating the object in an optically clear material; and

placing the encapsulated object proximate the one of the two principal surfaces of the recording medium.

5. The method of claim 4 wherein encapsulating the object in the optically clear material comprises encapsulating the object in an optically clear cement index matched to a cover glass.

6. The method of claim 1 wherein placing the object comprises:

placing a conventional volume hologram of a tangible object proximate the one of the two principal surfaces of the recording medium.

7. The method of claim 6 wherein the conventional volume hologram is encapsulated between flat glass plates, and wherein the conventional volume hologram is recorded in one of dichromated gelatin (DCG), photopolymer and silver halide.

8. The method of claim 6 wherein placing the conventional volume hologram comprises:

placing the conventional volume hologram at an angle with respect to any of the two principal surfaces of the recording medium.

9. The method of claim 1 further comprising:

reproducing holographic images of the object based, at least in part, on the first and second interference structures formed in the recording medium.

10. The method of claim 1 wherein providing the recording medium comprises:

providing a recording medium configured to be structurally modified when exposed to interfering and non-interfering portions of radiation beams, the structurally modified recording medium including, when viewed in a two-dimensional cross-section along one of the axes of the recording medium;

a plurality of equally spaced steps of fine-sized periodicity superimposed upon a plurality of deep depressions of substantially coarse-sized periodicity, wherein the structurally modified recording medium is configured to produce in reflection single and multiple colors in a broad spectral range when illuminated by a source of light.

11. A system to record a holographic image, the system comprising:

a recording medium having two principal surfaces and configured to record holographic image of an object placed proximate one of the two principal surfaces of the recording medium; and

a radiation source to direct radiation beams at another surface of the two principal surfaces of the recording medium at an angle with respect to a normal to the other of the two principal surfaces of the recording medium such that a resultant radiation beam reflected from the object interfere with a resultant first reference beam progressing in a direction that at least partly is similar to a progression direction of the resultant radiation beam reflected from the object, both beams being separated by a small angle such that a first interference fringe structure is formed in the recording medium that is inclined at an angle with respect to any of the two principal surfaces of the recording medium, and such that a resultant second reference beam progresses in a general direction that at least partly is opposite to the progression direction of the resultant radiation beam reflected from the object such that a second, fine-sized, set of interference fringes is formed in the recording medium, the second set of interference fringes being inclined with respect to the any of the two principal surfaces of the recording medium.

12. The system of claim 11 wherein the radiation source is a laser light source.