Electro-optical device utilizing an array of plasmonic field-effect transistors

Patent metadata

Field	Value
Publication number	US-2018248268-A1
Application number	US-201815901408-A
Country	US
Kind code	A1
Filing date	Feb 21, 2018
Priority date	Feb 24, 2017
Publication date	Aug 30, 2018
Grant date	—

Abstract

An electro-optical device using a plasmonic metasurface. The electro-optical device includes an electro-optical substrate and an array(s) of plasmonic unit cells forming a plasmonic metasurface fabricated on the substrate, where each of the plasmonic unit cells mimics a field-effect transistor. In each of the plasmonic unit cells, there is a drain and a source antenna separated from each other via a gap. In such a structure, a gate contact is not required thereby simplifying device fabrication. Furthermore, the device can be scaled to cover a large frequency range and have a flexible optical response, which is used to detect the presence of biomolecules. For example, the presence of a biomolecule is detected by observing a change in the electrical properties of the substrate in the gap region caused by a change in the substrate temperature which was caused by a change in the optical absorption of the plasmonic unit cell(s).

First claim

1 . An electro-optical device, comprising:
an electro-optical substrate; and one or more arrays of plasmonic unit cells forming a plasmonic metasurface fabricated on said electro-optical substrate, wherein each of said plasmonic unit cells mimics a field-effect transistor.

2 . The electro-optical device as recited in claim 1 , wherein each of said plasmonic unit cells comprises:
a drain antenna; and a source antenna separated from said drain antenna by a gap.

3 . The electro-optical device as recited in claim 2 , wherein each of said plasmonic unit cells further comprises:
a drain wire attached to said drain antenna; and a source wire attached to said source antenna.

4 . The electro-optical device as recited in claim 3 , wherein said drain and source wires run along the y-direction.

5 . The electro-optical device as recited in claim 2 , wherein said drain and source antennas function as electrodes, wherein a DC or AC or pulsed voltage between said drain and source antennas control the optical properties of said electro-optical substrate in said gap.

6 . The electro-optical device as recited in claim 1 , wherein said electro-optical substrate comprises a doped semiconductor.

7 . The electro-optical device as recited in claim 1 , wherein said electro-optical substrate comprises band-gap material.

8 . The electro-optical device as recited in claim 1 , wherein said electro-optical substrate comprises a phase transition metal-oxide.

9 . The electro-optical device as recited in claim 1 , wherein said electro-optical substrate is a thermochromic substrate.

10 . The electro-optical device as recited in claim 1 , wherein said electro-optical device is implemented in a photodetector array.

11 . The electro-optical device as recited in claim 1 , wherein said electro-optical device is implemented in an optical modulator.

12 . The electro-optical device as recited in claim 1 , wherein said electro-optical device is implemented in a multispectral imaging device.

13 . The electro-optical device as recited in claim 1 , wherein said electro-optical device is implemented in a tunable filter.

14 . The electro-optical device as recited in claim 2 , wherein said gap functions as an active region of said electro-optical device.

15 . The electro-optical device as recited in claim 2 , wherein a gradient of optical fields around a tip of said drain and source antennas and above said gap traps a biomolecule.

16 . The electro-optical device as recited in claim 3 , wherein a voltage applied to said drain and source wires causes biomolecules to attract to said drain and source wires.

17 . The electro-optical device as recited in claim 2 , wherein a voltage applied to said drain and source antennas results in trapping a biomolecule in said gap.

18 . A method for detecting biomolecules, the method comprising:
detecting a change in physical properties of a thermochromic substrate based on a change in temperature of said thermochromic substrate which is based on a change in an amount of optical absorption due to a presence of a biomolecule with an absorption fingerprint that matches a resonance frequency of an array of plasmonic unit cells; and detecting a presence of a biomolecule in response to detecting said change in said physical properties of said thermochromic substrate.

19 . The method as recited in claim 18 , wherein said change in said amount of optical absorption occurs at a unit cell of said array of plasmonic unit cells forming a plasmonic metasurface fabricated on said thermochromic substrate.

20 . The method as recited in claim 19 , wherein said thermochromic substrate comprises a transition metal-oxide.

21 . The method as recited in claim 18 , wherein said physical properties comprise one of the following: electrical conductivity and infrared (IR) transmittance.

Assignees

• Univ Texas

Inventors

• Shvets Gennady
• Dabidian Nima

Classifications

• H01Q15/0086 Primary

  said selective devices having materials with a synthesized negative refractive index, e.g. metamaterials or left-handed materials · CPC title

• G02F2203/11

  involving infrared radiation · CPC title

• G02B5/28

  Interference filters · CPC title

• H10F30/282

  Insulated-gate field-effect transistors [IGFET], e.g. MISFET [metal-insulator-semiconductor field-effect transistor] phototransistors · CPC title

• G01N33/54373 Primary

  involving physiochemical end-point determination, e.g. wave-guides, FETS, gratings · CPC title