Graphene-based plasmonic slot electro-optical modulator

Patent metadata

Field	Value
Publication number	US-2018246350-A1
Application number	US-201815905167-A
Country	US
Kind code	A1
Filing date	Feb 26, 2018
Priority date	Feb 24, 2017
Publication date	Aug 30, 2018
Grant date	—

Abstract

An electro-optical modulator using a graphene-based plasmonic slot is disclosed. The electro-optical modulator is comprised of a substrate layer, a dielectric spacer, a graphene layer, a first metal layer, and a second metal layer. The metal layers create a plasmonic slot that modulates between a light absorptive and light transparent state depending on the application of voltage across the modulator. Two or four graphene layers may be used to reduce power consumption and the size of the modulator.

First claim

1 . An electro-optical modulator comprised of:
a substrate layer; a first contact and a second contact disposed on the substrate layer; a dielectric spacer disposed on the substrate layer; a first graphene layer disposed on the dielectric spacer; a first metal layer and a second metal layer disposed on the graphene layer, forming a plasmonic slot; wherein, when a gating voltage is applied across the dielectric spacer and the graphene layer, the plasmonic slot modulates between a state of light absorption and light transparency.

2 . The electro-optical modulator of claim 1 , wherein the modulator is comprised of a second graphene layer disposed above the first graphene layer, such that the dielectric layer is sandwiched between the first graphene layer and the second graphene layer.

3 . The electro-optical modulator of claim 1 , where the modulator is comprised of a third graphene layer and a fourth graphene layer, wherein the first graphene layer, the second graphene layer, the third graphene layer, and the fourth graphene layer enclose the first metal layer, the second metal layer, and the plasmonic slot.

4 . The electro-optical modulator of claim 3 , wherein the first contact and the second contact are each comprised of a top layer of a conductive metal and a bottom layer of chromium.

5 . The electro-optical modulator of claim 1 , wherein the plasmonic slot has a height of 50 nm and a width of 50 nm.

6 . The electro-optical modulator of claim 1 , wherein the plasmonic slot has a reduced resistance.

7 . The electro-optical modulator of claim 1 , wherein the graphene layer has a selectively tuned Fermi level.

9 . The electro-optical modulator of claim 1 , wherein the dielectric spacer is comprised of silicon dioxide (SiO 2 ), aluminum oxide (Al 2 O 3 ), or hafnium oxide (HfO 2 ).

10 . The electro-optical modulator of claim 1 , wherein the first metal layer and the second layer are metal blocks fabricated by a single lithography and deposition step.

11 . The electro-optical modulatory of claim 1 , wherein said first contact and second contact are deposited on the substrate layer, said dielectric spacer is deposited on the substrate layer, said first graphene layer is deposited on the dielectric spacer, and said first metal layer and second metal layer are deposited on the graphene layer, forming a plasmonic slot.

12 . The electro-optical modulator of claim 1 , wherein the substrate layer is comprised of Si, Ge, InAs, InGaAs, or InP.

13 . An electro-optical modulator comprising:
a substrate; a first graphene layer positioned on the substrate and having a first contact; a dielectric spacer positioned on the first graphene layer; a second graphene layer positioned on the dielectric layer spaced from the first graphene layer, said second graphene layer having a second contact; and a first block and a second block positioned on the second graphene layer and having an optical waveguide slot therebetween, whereby a gating voltage is applied across the first contact and the second contact to control an optical signal passing through the optical waveguide slot.

14 . The modulator of claim 13 , further comprising:
a third graphene layer coupled to the first graphene layer and extending over a top of the first and/or second block; and a fourth graphene layer coupled to the second graphene layer and extending over the top of the first and/or second block.

15 . The modulator of claim 14 , wherein the third graphene layer extends over at least a portion of the fourth graphene layer to cover the plasmonic slot.

Assignees

• Univ George Washington

Inventors

• Ma Zhizhen
• Sorger Volker J

Classifications

• G02F2202/16

  conductive · CPC title

• G02F1/0107

  Gaskets, spacers or sealing of cells; Filling and closing of cells · CPC title

• G02F2203/10

  plasmon · CPC title

• G02F2202/02

  organic material · CPC title

• G02F1/0081

  Electric or magnetic properties · CPC title