Photon number resolving superconducting detector

Patent metadata

Field	Value
Publication number	US-11988554-B2
Application number	US-202318103413-A
Country	US
Kind code	B2
Filing date	Jan 30, 2023
Priority date	May 1, 2018
Publication date	May 21, 2024
Grant date	May 21, 2024

Abstract

A method of resolving a number of photons received by a photon detector includes optically coupling a waveguide to a superconducting wire having alternating narrow and wide portions; electrically coupling the superconducting wire to a current source; and electrically coupling an electrical contact in parallel with the superconducting wire. The electrical contact has a resistance less than a resistance of the superconducting wire while at least one narrow portion of the superconducting wire is in a non-superconducting state. The method includes providing to the superconducting wire, from the current source, a current configured to maintain the superconducting wire in a superconducting state in the absence of incident photons; receiving one or more photons via the waveguide; measuring an electrical property of the superconducting wire, proportional to a number of photons incident on the superconducting wire; and determining the number of received photons based on the electrical property.

First claim

What is claimed is:

1. A photon detector, comprising:
a superconducting component having a plurality of alternating narrow and wide portions;
a current source electrically-coupled to the superconducting component and configured to supply the superconducting component with electrical current; and
a waveguide optically-coupled to a plurality of narrow portions from the plurality of alternating narrow and wide portions, the optical waveguide tapered such that a first narrow portion of the plurality of alternating narrow and wide portions is coupled to a first portion of the waveguide having a first width and a second narrow portion of the plurality of alternating narrow and wide portions is coupled to a second portion of the waveguide having a second width, the second width being larger than the first width.

2. The photon detector of claim 1 , wherein the second portion of the waveguide is downstream of the first portion of the waveguide.

3. The photon detector of claim 1 , wherein a coupling efficiency of the first portion of the waveguide with the first narrow portion is less than a coupling efficiency of the second portion of the waveguide with the second narrow portion.

4. The photon detector of claim 1 , further comprising a mirror optically-coupled to an end of the waveguide.

5. The photon detector of claim 1 , further comprising an electrical contact electrically-coupled in parallel with the superconducting component.

6. The photon detector of claim 1 , further comprising a readout circuit electrically-coupled to the superconducting component and configured to measure an electrical property of the superconducting component, wherein the electrical property is indicative of a number of photons incident to the superconducting component.

7. The photon detector of claim 6 , wherein the electrical property comprises a voltage across the superconducting component or an impedance of the superconducting component.

8. The photon detector of claim 6 , wherein the readout circuit is configured to measure a voltage across an electrical contact electrically-coupled in parallel with the superconducting component.

9. The photon detector of claim 1 , further comprising a photon source coupled to the waveguide and configured to probabilistically generate photons.

10. The photon detector of claim 1 , wherein each narrow portion of the plurality of alternating narrow and wide portions is straight to reduce current crowding effects within the narrow portion.

11. The photon detector of claim 1 , wherein at least one wide portion of the plurality of alternating narrow and wide portions is bent.

12. The photon detector of claim 1 , wherein narrow portions of the plurality of alternating narrow and wide portions each have a first width and wide portions of the plurality of alternating narrow and wide portions each have a second width, the second width being greater than the first width.

13. The photon detector of claim 1 , wherein each wide portion includes a bend, and wherein an inside bend radius of each wide portion is equal to a width of the wide portion.

14. The photon detector of claim 1 , wherein the current source is configured to maintain the superconducting component in a superconducting state in the absence of incident photons from the waveguide.

15. The photon detector of claim 1 , wherein:
narrow portions of the plurality of alternating narrow and wide portions are configured to transition from a superconducting state to a non-superconducting state in response to an incident photon from the waveguide, and
wide portions of the plurality of alternating narrow and wide portions are sized so as to remain in the superconducting state regardless of a state of the narrow portions.

16. The photon detector of claim 1 , wherein the superconducting component is tapered between narrow portions and wide portions of the plurality of alternating narrow and wide portions to reduce current crowding effects.

17. A method of resolving a number of co-incident photons, comprising:
optically coupling a waveguide to a superconducting component having a plurality of alternating narrow and wide portions, wherein the waveguide is tapered such that a first narrow portion of the plurality of alternating narrow and wide portions is coupled to a first portion of the waveguide having a first width and a second narrow portion of the plurality of alternating narrow and wide portions is coupled to a second portion of the waveguide having a second width, the second width being larger than the first width;
electrically coupling the superconducting component to a current source;
providing a current from the current source to the superconducting component, the current configured to maintain the superconducting component in a superconducting state in the absence of incident photons;
receiving a plurality of photons via the waveguide;
measuring an electrical property of the superconducting component, wherein the electrical property is proportional to a number of photons incident on the superconducting component; and
determining the number of photons incident on the superconducting component based on the electrical property.

18. The method of claim 17 , wherein the second portion of the waveguide is downstream of the first portion of the waveguide.

19. The method of claim 17 , wherein a coupling efficiency of the first portion of the waveguide with the first narrow portion is less than a coupling efficiency of the second portion of the waveguide with the second narrow portion.

20. The method of claim 17 , further comprising reflecting at least one of the plurality of photons at an end of the waveguide so that the at least one of the plurality of photons travels along at least part of the waveguide more than once.

Assignees

• Psiquantum Corp

Inventors

• Najafi Faraz
• Dudley Eric
• Thompson Mark

Classifications

• G01J1/44 Primary

  Electric circuits {(for command of an exposure part G03B7/02)} · CPC title

• G01J1/0407

  Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings · CPC title

• G01J2001/4446

  Type of detector · CPC title

• G01J1/42 Primary

  using electric radiation detectors (optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10) · CPC title

• G01J2001/442

  Single-photon detection or photon counting · CPC title