Nanovoided tunable birefringence

Patent metadata

Field	Value
Publication number	US-11233189-B2
Application number	US-201916262433-A
Country	US
Kind code	B2
Filing date	Jan 30, 2019
Priority date	Dec 11, 2018
Publication date	Jan 25, 2022
Grant date	Jan 25, 2022

Abstract

A form birefringent optical element includes a structured layer and a dielectric environment disposed over the structured layer. At least one of the structured layer and the dielectric environment includes a nanovoided polymer, the nanovoided polymer having a first refractive index in an unactuated state and a second refractive index different than the first refractive index in an actuated state. Actuation of the nanovoided polymer can be used to reversibly control the form birefringence of the optical element. Various other apparatuses, systems, materials, and methods are also disclosed.

First claim

What is claimed is:

1. A form birefringent optical element comprising:
a structured layer comprising a non-nanovoided polymer;
a dielectric environment disposed over the structured layer;
a primary electrode; and
a secondary electrode overlapping at least a portion of the primary electrode,
wherein:
the dielectric environment comprises a nanovoided polymer, the nanovoided polymer having a first refractive index in an unactuated state and a second refractive index different than the first refractive index in an actuated state;
the nanovoided polymer is disposed between the primary electrode and the secondary electrode;
the actuated state corresponds to an electric potential applied between the primary electrode and secondary electrode;
the second refractive index results from a compression of nanovoids in the nanovoided polymer by the electric potential in the actuated state; and
the dielectric environment and the structured layer are refractive index matched when the nanovoided polymer is in the actuated state.

2. The optical element of claim 1 , wherein the structured layer comprises a grating having a period in at least one dimension of less than λ/5, where λ is a wavelength of light incident on the optical element.

3. The optical element of claim 1 , wherein the structured layer comprises a substantially dense polymer.

4. The optical element of claim 1 , wherein the first refractive index is equal to a refractive index of the dielectric environment.

5. The optical element of claim 1 , wherein the second refractive index is equal to a refractive index of the dielectric environment.

6. The optical element of claim 1 , wherein the nanovoided polymer is configured to have a higher refractive index in the actuated state due to the compression of the nanovoids in the nanovoided polymer.

7. The optical element of claim 1 , wherein the nanovoided polymer abuts the primary electrode and the secondary electrode.

8. The optical element of claim 1 , wherein the nanovoided polymer comprises a uniform void topology.

9. The optical element of claim 1 , wherein the nanovoided polymer comprises a non-uniform void topology.

10. A form birefringent optical element comprising:
a structured layer comprising a non-nanovoided polymer;
a dielectric environment disposed over the structured layer;
a primary electrode; and
a secondary electrode overlapping at least a portion of the primary electrode;
wherein;
the dielectric environment comprises a nanovoided polymer layer and the nanovoided polymer layer is disposed between and abutting the primary electrode and the secondary electrode,
the nanovoided polymer layer has a first refractive index in an unactuated state and a second refractive index different than the first refractive index in an actuated state;
the actuated state corresponds to an electric potential applied between the primary electrode and secondary electrode; and
the second refractive index results from a compression of nanovoids in the nanovoided polymer layer by the electric potential in the actuated state; and
the dielectric environment and the structured layer are refractive index matched when the nanovoided polymer layer is in the actuated state.

11. The optical element of claim 10 , wherein the dielectric environment is disposed directly over the structured layer.

12. A method comprising:
forming a primary electrode;
forming a structured layer over the primary electrode, wherein the structured layer comprises a non-nanovoided polymer;
forming a dielectric layer over the structured layer; and
forming a secondary electrode;
wherein:
the dielectric layer comprises a nanovoided polymer and the nanovoided polymer is disposed between and abutting the primary electrode and the secondary electrode;
the nanovoided polymer has a first refractive index in an unactuated state and a second refractive index different than the first refractive index in an actuated state;
the actuated state corresponds to an electric potential applied between the primary electrode and secondary electrode;
the second refractive index results from a compression of nanovoids in the nanovoided polymer by the electric potential in the actuated state; and
the dielectric layer and the structured layer are refractive index matched when the nanovoided polymer is in the actuated state.

13. The method of claim 12 , further comprising shining light on the structured layer, wherein the structured layer comprises a grating having a period in at least one dimension of less than λ/5, where λ is a wavelength of the light.

14. The method of claim 12 , further comprising applying the electric potential between the primary electrode and the secondary electrode.

15. The method of claim 12 , wherein the secondary electrode is formed directly over the structured layer.

16. The optical element of claim 10 , wherein the structured layer comprises a grating having a period in at least one dimension of less than λ/5, where λ is a wavelength of light incident on the optical element.

17. The optical element of claim 10 , wherein the nanovoided polymer layer is configured to have a higher refractive index in the actuated state due to the compression of the nanovoids in the nanovoided polymer layer.

18. The optical element of claim 10 , wherein the nanovoided polymer layer comprises a uniform void topology.

19. The optical element of claim 10 , wherein the nanovoided polymer layer comprises a non-uniform void topology.

Assignees

• Facebook Tech Llc

Inventors

• Diest Kenneth
• Ouderkirk Andrew John
• Andreev Gregory Olegovic
• Shipton Erik
• Malhotra Tanya
• Silverstein Barry David
• Liao Christopher Yuan Ting

Classifications

• G02B2207/107

  Porous materials, e.g. for reducing the refractive index · CPC title

• G02B5/045

  Prism arrays · CPC title

• G02B3/0087

  with index gradient · CPC title

• G02B3/00

  Simple or compound lenses · CPC title

• B29K2995/0026

  Transparent · CPC title