Spatial light modulator using phase-change materials with improved fill factor

Patent metadata

Field	Value
Publication number	US-11808937-B1
Application number	US-202117512562-A
Country	US
Kind code	B1
Filing date	Oct 27, 2021
Priority date	Jun 12, 2017
Publication date	Nov 7, 2023
Grant date	Nov 7, 2023

Abstract

A method of providing a spatial light modulator comprising: providing a substrate; providing a first phase change material cell on the substrate, the first phase change material cell comprising: a first electrical heater on the substrate; a first optical reflector layer on the electrical heater; and a first phase change material layer on the optical reflector layer; and providing at least a second phase change material cell on the substrate, the second phase change material cell comprising: a second electrical heater on the substrate; a second optical reflector layer on the second electrical heater; a second phase change material layer on the second optical reflector layer; and providing a light absorber layer between the first phase change material cell and the second phase change material cell.

First claim

What is claimed is:

1. A method of providing a spatial light modulator comprising:
providing a substrate; and
providing a first phase change material cell on the substrate, the first phase change material cell comprising:
a first electrical heater on the substrate;
a first optical reflector layer on the first electrical heater; and
a first phase change material layer on the first optical reflector layer;
providing at least a second phase change material cell on the substrate, the second phase change material cell comprising:
a second electrical heater on the substrate;
a second optical reflector layer on the second electrical heater;
a second phase change material layer on the second optical reflector layer; and
providing a light absorber layer between the first phase change material cell and the second phase change material cell.

2. The method of claim 1 further comprising:
depositing the first phase change material layer on the first optical reflector layer at room temperature by sputtering;
wherein the phase change material layer comprises a SbTe alloy, or a Ge or an In doped SbTe alloy.

3. The method of claim 1 further comprising:
providing an anti-reflection coating on the first phase change material layer.

4. The method of claim 1 further comprising:
providing a thermal barrier between the first electrical heater and the substrate;
wherein the thermal barrier comprises a dielectric or SiO2.

5. The method of claim 1 wherein the first optical reflector layer is metallic.

6. The method of claim 1 :
wherein when the first phase change material layer is in an amorphous phase, light may be transmitted through the first phase change material layer; and
wherein when the first phase change material layer is in a crystalline phase, light is absorbed and not transmitted through the first phase change material layer.

7. The method of claim 1 wherein the first electrical heater comprises TiW, and is a single zone heater or a dual zone heater.

8. A method of providing a spatial light modulator comprising:
providing a substrate; and
providing a phase change material cell on the substrate, the phase change material cell comprising:
an electrical heater on the substrate;
an optical reflector layer on the electrical heater; and
a phase change material layer on the optical reflector layer;
wherein when the phase change material layer is in an amorphous phase, an optical extinction coefficient is substantially zero for wavelengths ranging from 1 to 17 micrometers; and
wherein when the phase change material layer is in a crystalline phase, the optical extinction coefficient is substantially greater than one for wavelengths ranging from 1 to 17 micrometers.

9. A method of providing a spatial light modulator comprising:
providing a substrate; and
providing a phase change material cell on the substrate, the phase change material cell comprising:
an electrical heater on the substrate;
an optical reflector layer on the electrical heater; and
a phase change material layer on the optical reflector layer;
wherein the electrical heater comprises one of:
a single zone heater comprising:
a first electrode and a second electrode coupled to the electrical heater; and
a heater controller coupled to the first electrode and the second electrode; and

a dual zone heater comprising:
a first electrode and a second electrode coupled to the electrical heater;
a second electrical heater;
a third electrode and a fourth electrode coupled to the second electrical heater; and
a heater controller coupled to the first, second, third and fourth electrodes.

Assignees

• Hrl Lab Llc

Inventors

• Moon Jeong-Sun
• Seo Hwa Chang
• Son Kyung-Ah
• Lee Kangmu

Classifications

• G02B26/0833 Primary

  the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD (G02B26/0825 takes precedence; micromechanical devices in general B81B) · CPC title

• G02B27/0977

  Reflective elements · CPC title

• G02F1/133553

  Reflecting elements (associated to illuminating devices G02F1/133605) · CPC title

• G02F1/17 Primary

  based on variable-absorption elements not provided for in groups G02F1/015 - G02F1/169 · CPC title

• G02F2203/11

  involving infrared radiation · CPC title