Meta-structure and tunable optical device including the same

Patent metadata

Field	Value
Publication number	US-9851589-B2
Application number	US-201615233036-A
Country	US
Kind code	B2
Filing date	Aug 10, 2016
Priority date	Aug 10, 2015
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

A meta-structure and a tunable optical device including the same are provided. The meta-structure includes a plurality of metal layers spaced apart from one another, an active layer spaced apart from the plurality of metal layers and having a carrier concentration that is tuned according to an electric signal applied to the active layer and the plurality of metal layers, and a plurality of dielectric layers spaced apart from one another and each having one surface contacting a metal layer among the plurality of metal layers and another surface contacting the active layer.

First claim

What is claimed is:

1. A meta-structure comprising:
a plurality of metal layers spaced apart from one another;
an active layer spaced apart from the plurality of metal layers and having a carrier concentration that is tuned according to an electric signal applied to the active layer and the plurality of metal layers; and
a plurality of dielectric layers spaced apart from one another and each having one surface contacting a metal layer among the plurality of metal layers and another surface contacting the active layer.

2. The meta-structure of claim 1 , further comprising a voltage-applying portion configured to apply a voltage between the active layer and the plurality of dielectric layers to generate the electrical signal.

3. The meta-structure of claim 2 , wherein the voltage-applying portion is configured to a same voltage between the active layer and each of the plurality of metal layers.

4. The meta-structure of claim 2 , wherein, when a voltage is applied between the active layer and the plurality of metal layers, carrier accumulation layers having a tunable charge density are formed on ends of the active layer that contact the plurality of dielectric layers among regions of the active layer.

5. The meta-structure of claim 2 , wherein the active layer comprises a transparent conductive oxide, a nitride, or a doped semiconductor material.

6. The meta-structure of claim 1 , wherein the dielectric layer comprises any one among SiO 2 , Al 2 O 3 , HfO 2 , HfSiO 4 , a transition metal oxide, and electrochromic polymer.

7. The meta-structure of claim 1 , wherein a dielectric breakdown electric field E br and a direct current (DC) dielectric constant k diel of one of the dielectric layers satisfy the following equation:

k
diel

⁢

E
br

≥

|
e
|
Nd

ɛ
0

,

where N is a carrier concentration of the carrier accumulation layers, e is a quantity of electric charge of electrons, ∈ 0 is a permittivity of a vacuum, and d is a Debye length.

8. The meta-structure of claim 1 , wherein the metal layer comprises one among Cu, Al, Ni, Fe, Co, Zn, Ti, Ru, Rh, Pd, Pt, Ag, Os, Ir, Au, and TiN.

9. A tunable optical device comprising:
a meta-structure comprising:
a plurality of metal layers spaced apart from one another;
an active layer spaced apart from the plurality of metal layers and having a carrier concentration that is tuned according to an electric signal applied to the active layer and the plurality of metal layers; and
a plurality of dielectric layers spaced apart from one another and each having one surface contacting a metal layer among the plurality of metal layers and another surface contacting the active layer,

a voltage-applying portion configured to apply a voltage between the active layer and the plurality of metal layers to generate the electric signal; and
a controller configured to control the voltage to be applied between the active layer and the plurality of metal layers by the voltage-applying portion according to an optical property to be controlled in the meta-structure.

10. The tunable optical device of claim 9 , wherein the controller is configured to control the voltage so that birefringence of the meta-structure is tuned.

11. The tunable optical device of claim 9 , wherein the controller is configured to control the voltage so that dichroism of the meta-structure is tuned.

12. The tunable optical device of claim 9 , wherein the controller is configured to control the voltage so that an optical band gap of the meta-structure is tuned.

13. The tunable optical device of claim 9 , further comprising:
a plurality of meta-structures arranged two-dimensionally; and
a circuit board comprising a circuit element configured to apply a voltage to each of the plurality of meta-structures.

14. The tunable optical device of claim 13 , wherein an extraordinary axis of each of the meta-structures is defined as a direction along which the plurality of metal layers, the active layer, and the plurality of dielectric layers are spaced apart, and the extraordinary axis of each of the meta-structures is in parallel to a plane defined by the two-dimensional arrangement.

15. The tunable optical device of claim 13 , wherein an extraordinary axis of each of the meta-structures is defined as a direction along which the plurality of metal layers, the active layer, and the plurality of dielectric layers are spaced apart, and the extraordinary axis of each of the meta-structures is perpendicular to a plane defined by the two-dimensional arrangement.

16. A display apparatus comprising:
a first substrate comprising a first polarization plate;
a second substrate comprising a second polarization plate;
an optical modulator provided between the first substrate and the second substrate and comprising a plurality of meta-structures, each of the meta-structures comprising:
a plurality of metal layers spaced apart from one another;
an active layer spaced apart from the plurality of metal layers and having a carrier concentration that is tuned according to an electric signal applied to the active layer and the plurality of metal layers; and
a plurality of dielectric layers spaced apart from one another and each having one surface contacting a metal layer among the plurality of metal layers and another surface contacting the active layer; and

a circuit board comprising a circuit element configured to apply a voltage to each of the plurality of meta-structures to generate the electrical signal.

17. The display apparatus of claim 16 , further comprising a backlight unit configured to provide light to be modulated by the optical modulator.

18. An optical memory device comprising:
a meta-structure comprising:
a plurality of metal layers spaced apart from one another;
an active layer spaced apart from the plurality of metal layers and having a carrier concentration that is tuned according to an electric signal applied to the active layer and the plurality of metal layers; and
a plurality of dielectric layers spaced apart from one another and each having one surface contacting a metal layer among the plurality of metal layers and another surface contacting the active layer;

a first quantum emitter and a second quantum emitter, the first and second quantum emitters provided adjacent to the meta-structure and configured to exchange optical energy with each other; and
a controller configured to apply a voltage for controlling an optical band gap of the meta-structure to the meta-structure.

19. The optical memory device of claim 18 , wherein the first and second quantum emitters are provided on the meta-structure or embedded in the meta-structure.

20. The optical memory device of claim 18 , wherein the controller is configured to apply a first voltage to the meta-structure when the second quantum emitter is excited by optical energy emitted according to a change of a state of the first quantum emitter and to app

Assignees

• Samsung Electronics Co Ltd
• California Inst Of Techn

Inventors

• Han Seunghoon
• PAPADAKIS Georgia Theano
• Atwater Harry

Classifications

• G11C13/048

  using other optical storage elements · CPC title

• G02F1/0105

  Illuminating devices · CPC title

• G02B1/002

  made of materials engineered to provide properties not available in nature, e.g. metamaterials · CPC title

• G02F2202/30

  Metamaterials · CPC title

• G02F1/0018

  Electro-optical materials · CPC title