Metamaterial photocathode for detection and imaging of infrared radiation

Patent metadata

Field	Value
Publication number	US-10236165-B2
Application number	US-201816055080-A
Country	US
Kind code	B2
Filing date	Aug 4, 2018
Priority date	Nov 28, 2016
Publication date	Mar 19, 2019
Grant date	Mar 19, 2019

Abstract

Exemplary metamaterial photocathodes enable detection of light from visible through long wave infrared wavelengths. Metamaterial stacks, comprising gold, silicon, and cesium-oxide, coupled to a semiconductor allow hot electrons to efficiently enter a vacuum. The hot electrons are multiplied in a multichannel plate and directly through another vacuum towards a phosphorus screen.

First claim

The invention claimed is:

1. A metamaterial photocathode (MMP) comprising:
a MMP assembly comprising:
a first and a second metal contact;
a first substrate comprising a first semiconductor, wherein the first substrate has a first side with opposing first and second ends, wherein the first and second metal contacts are coupled to the first and second ends, respectively, wherein the first substrate has a second side opposing the first side;
a plurality of metamaterial stacks (MMS) each comprising:
a metamaterial absorber (MMA) layer comprising a metal compound, wherein the MMA layer is coupled to the second side of the first substrate;
a second substrate layer comprising a p-type second semiconductor, wherein the second substrate layer is coupled to the MMA layer; and
a negative electron affinity (NEA) layer coupled to the second substrate layer;

an electron detector;
a first vacuum layer between the electron detector and the MMP assembly; and
wherein an electrical circuit connects the first metal contact, electron detector, and second metal contact such that applying a current through the circuit creates an electric field across the MMP;
wherein electron hole pairs (EHP) comprising a first plurality of electrons form within the first and second substrate layers when infrared radiation strikes the MMP assembly, wherein the electric field draws the first plurality of electrons from the first and second substrate layers towards the electron detector and draws a first plurality of electron holes towards the first and second metal contacts.

2. The MMP of claim 1 , the first and second metal contacts comprising gold.

3. The MMP of claim 1 , the p-type second semiconductor comprising silicon.

4. The MMP of claim 1 , the first semiconductor comprising a p-type semiconductor.

5. The MMP of claim 1 , the first semiconductor comprising a n-type semiconductor.

6. The MMP of claim 1 , the electron detector comprising a microchannel plate and a phosphorus screen or anode.

7. The MMP of claim 1 , the NEA layer comprising cesium oxide.

Assignees

• Us Navy

Inventors

• Conley Benjamin R

Classifications

• H01J47/00

  Tubes for determining the presence, intensity, density or energy of radiation or particles ({discharge tubes using igniting by associated radioactive materials or fillings, e.g. current stabilising tubes H01J17/32} ; photoelectric discharge tubes not involving the ionisation of a gas H01J40/00 {; discharge tubes for measuring the pressure, partial pressure of introduced gas or for detecting presence of gas H01J41/02; ionisation chambers using a solid dielectric G01T3/008}) · CPC title

• H01J49/08

  Electron sources, e.g. for generating photo-electrons, secondary electrons or Auger electrons · CPC title

• H01J40/16

  having photo- emissive cathode, e.g. alkaline photoelectric cell (operating with secondary emission H01J43/00) · CPC title

• H01J40/06 Primary

  Photo-emissive cathodes · CPC title

• H01J43/246

  Microchannel plates [MCP] (image amplification tubes using MCP H01J31/507) · CPC title