# US 2010/0165431 A1 · Dynamically reconfigurable holograms with electronically erasable programmable intermediate layers

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- Number: US 2010/0165431 A1
- Document ID: US20100165431A1
- Status: Published application
- Kind: A1
- Application number: 12/317,731
- Filed: 2008-12-29
- Published: 2010-07-01
- Earliest claimed: 2008-12-29
- Assignees: Hewlett-Packard Development Company, L.P.
- Inventors: Jingjing Li; Philip J. Kuekes; Shih-Yuan Wang
- Web page: https://patentgrep.com/patent/US20100165431A1

## CPC

- G03H 1/22: Processes or apparatus for obtaining an optical image from holograms (G03H1/26 - G03H1/34 take precedence)
- G03H 1/02: Details {of features involved during the holographic process; Replication of holograms without interference recording}
- G03H 1/2294: {Addressing the hologram to an active spatial light modulator}
- G03H 2001/0224: {Active addressable light modulator, i.e. Spatial Light Modulator [SLM]}
- G03H 2225/22: Electrically addressed SLM [EA-SLM]
- G03H 2225/32: Phase only
- G03H 2225/33: Complex modulation
- G03H 2225/60: Multiple SLMs
- G03H 2240/24: Index variations only
- Y10S 977/762: Nanowire or quantum wire, i.e. axially elongated structure having two dimensions of 100 nm or less
- Y10S 977/765: with specified cross-sectional profile, e.g. belt-shaped
- G03H: HOLOGRAPHIC PROCESSES OR APPARATUS (holograms, e.g. point holograms, used as ordinary optical elements G02B5/32; producing stereoscopic or other three-dimensional effects G02B30/00; diffraction-grating systems G02B27/44; systems using moiré fringes G02B27/60; optical logic elements G02F3/00; stereo-photography G03B35/00; photosensitive materials or processes for photographic purposes G03C; {stereo-photographic or similar processes G03C9/00}; apparatus for processing exposed photographic materials G03D; analogue computers performing mathematical operations with the aid of optical elements G06E3/00; authentication by radiation, of concealed information carried by holograms or diffraction gratings G06K19/16; holographic storage G11B7/0065, G11C13/04; {stereoscopic or other three dimensional effects in television systems H04N13/00})
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

Various embodiments of the present invention relate to dynamically reconfigurable hologram comprising a phase-modulation layer and an intensity-control layer. The phase modulation layer comprises an electronically programmable erasable negative index material crossbar. The crossbar includes a first layer of approximately parallel nanowires (502) and a second layer of approximately parallel nanowires (504) that overlay the nanowires in the first layer. The nanowires in the first and second layers have substantially regularly spaced fingers. The crossbar also includes resonant elements (812) comprising two fingers of a nanowire in the first layer, two fingers of a nanowire in the second layer, and an intermediate layer (1006,1302) sandwiched between the nanowire in the first layer and the nanowire in the second layer. The refractive index of each resonant element is controlled by changing the charge density within the intermediate layer.

## Claims

### Claim 1

An electronically programmable and erasable negative index material crossbar (500) comprising:
a first layer of approximately parallel nanowires (502), each nanowire having substantially regularly spaced fingers (612);
a second layer of approximately parallel nanowires (504) that overlay the nanowires in the first layer, each nanowire having substantially regularly spaced fingers (608), wherein the nanowires in the first layer are approximately perpendicular in orientation to the nanowires in the second layer; and
resonant elements (812) at nanowire intersections, each resonant element including two fingers of a nanowire in the first layer, two fingers of a nanowire in the second layer, and an intermediate layer (1006,1302) sandwiched between the nanowire in the first layer and the nanowire in the second layer, wherein the refractive index of each resonant element is controlled by a change in charge density within the intermediate layer.

### Claim 2 (depends on 1)

The crossbar of claim 1 wherein the intermediate layer further comprises:
a first dielectric insulation layer (1008) disposed adjacent to a nanowire in the first layer of nanowires (1002);
a second dielectric insulation layer (1010) disposed adjacent to a nanowire in the second layer of nanowires (1004) and having a relatively larger thickness than the first dielectric insulation layer; and
a floating gate (1012) sandwiched between the first dielectric insulation layer and the second dielectric insulation layer.

### Claim 3 (depends on 2)

The crossbar of claim 2 wherein the change in the charge density within the intermediate layer further comprises:
a voltage applied to the intermediate layer;
electrons tunneling through the first dielectric insulation layer into the conduction band of the floating gate; and
electrons trapped in the floating gate.

### Claim 4 (depends on 2)

The crossbar of claim 2 wherein the floating gate further comprises one of:
poly-silicon;
an element semiconductor; and
a compound semiconductor.

### Claim 5 (depends on 1)

The crossbar of claim 1 wherein the intermediate layer further comprises:
a first dielectric insulation layer (1008) disposed adjacent to a nanowire in the first layer of nanowires (1002);
a second dielectric insulation layer (1010) having a relatively larger thickness than the first dielectric insulation layer;
a floating gate (1012) sandwiched between the first dielectric insulation layer and the second dielectric insulation layer; and
a second semiconductor layer (1304) sandwiched between the second dielectric insulation layer and a nanowire in the second layer of nanowires (1004).

### Claim 6 (depends on 5)

The crossbar of claim 5 wherein the change in the charge density within the intermediate layer further comprises:
a voltage applied to the intermediate layer;
electrons tunnel through the first dielectric insulation layer into the conduction band of the floating gate;
electrons trapped in the floating gate; and
charge carriers redistributed in the second semiconductor layer.

### Claim 7 (depends on 5)

The crossbar of claim 5 wherein the floating gate and the second semiconductor layer further comprise one of:
poly-silicon;
an element semiconductor; and
a compound semiconductor.

### Claim 8 (depends on 1)

The crossbar of claim 1 wherein the nanowires in the first and second layers further comprise:
the finger of adjacent nanowires within the same layer are substantially aligned;
notches between fingers of nanowires in the first layer are substantially aligned with notches between fingers of the nanowires in the second layer; and
the cross-sectional dimensions of the nanowires in the first layer are relatively larger than the cross-sectional dimensions of the nanowires in the second layer.

### Claim 9 (depends on 1)

A dynamically reconfigurable hologram (1600) comprising:
a phase-control layer (1602) configured as a negative index material crossbar configured in accordance with claim 1 to form a two-dimensional array of phase-modulation pixels (1612); and
an intensity-control layer (1604) including a two-dimensional array of intensity-control pixels (1614), wherein one or more three-dimensional motion pictures can be produced by electronically addressing the individual phase-modulation pixels and intensity-control pixels in order to phase shift and control the intensity of light emanating from the pixels of the hologram.

### Claim 10 (depends on 9)

The hologram of claim 9 wherein the phase-modulation pixel further comprises an array of one or more resonant elements (1000,1300).

### Claim 11 (depends on 9)

The hologram of claim 9 wherein electronically addressing the phase-modulation pixels further comprises a voltage selectively applied to each phase-modulation pixel, each voltage changing the refractive index of a phase-modulation pixel.

### Claim 12 (depends on 11)

The hologram of claim 11 wherein changing the refractive index of a phase-modulation pixel further comprises a change in the charge density of an intermediate layer within each resonant element comprising the phase-modulation pixel.

### Claim 13 (depends on 9)

The hologram of claim 9 wherein electronically addressing the intensity-control pixels further comprises a voltage applied to each intensity-control pixel, each voltage changing the transparency of an intensity-control pixel.

### Claim 14 (depends on 9)

The hologram of claim 9 wherein the three-dimensional image can be produced by transmitting light through the hologram-producing system (1600) from a light source located opposite the three-dimensional image or reflecting light from the hologram from a light source located on the same side of the hologram as the one or more images produced by the hologram, wherein the light source further comprises a quasimonochromatic light source.

### Claim 15 (depends on 9)

A system for generating a three-dimensional image comprising:
a computer system (2502) including a processor and memory;
a dynamically reconfigurable hologram (1600) configured in accordance with claim 9 and coupled to the computer system; and
a light source (2504) positioned and configured to emit quasimonochromatic light into the hologram, wherein data representing one of more images is stored in the memory and the processor executes a computer program that displays the image data as one or more three-dimensional images by electronically addressing the phase-modulation pixels and the intensity-control pixels to phase shift and control the intensity of light emanating from the hologram.