IP Library › Granted Patent US 12,411,192
Granted Patent B2
US 12,411,192 · App. 18/307,451 · Granted Sep 9, 2025

Spin-based detection of terahertz and sub-terahertz electromagnetic radiation

Inventors: Jing Shi (Riverside, CA); Junxue Li (Riverside, CA)
Assignee: The Regents of the University of California
G01R33/1284G01N21/3586G01R33/075H10N50/80
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Quick Facts
Patent No.
US 12,411,192
App. No.
18/307,451
Granted
Sep 9, 2025
Kind
B2
Abstract

Systems and methods for spin-based detection of electromagnetic radiation at terahertz and sub-terahertz frequencies is provided. The detector can include a heterostructure and an electrical circuit. The heterostructure can include a first layer formed of an antiferromagnetic material (AFM) in contact with a second layer of a heavy metal (HM) and a third layer. The third layer can generate an effective field oriented approximately parallel to an easy axis of the first layer and approximately parallel to a propagation direction of electromagnetic radiation. The circuit can be in electrical communication with the second layer. The first layer can inject a spin current into the second layer in response to receipt of electromagnetic radiation having a sub-terahertz or terahertz frequency. The second layer can convert the injected spin current into a potential difference. The circuit can be configured to output a signal corresponding to the potential difference.

Claims (33)

1. A electromagnetic radiation detector, comprising:

a first layer including an antiferromagnetic material (AFM);

a second layer, in contact with the first layer, the second layer including a heavy metal (HM);

a third layer opposite the second layer and in contact with the first layer, the third layer configured to generate an effective field having a direction oriented approximately parallel to an easy axis of a crystal lattice of the antiferromagnetic material and to a direction of propagation of incident electromagnetic radiation; and

an electrical circuit in electrical communication with the second layer;

wherein the first layer is configured to inject a spin current into the second layer in response to receipt of electromagnetic radiation having a frequency within the range of sub-terahertz or terahertz frequencies;

wherein the second layer is configured to generate a potential difference in response to receipt of the spin current; and

wherein the circuit is configured to output an electrical signal corresponding to the potential difference.

2. The detector of claim 1 , wherein the second layer includes a topological insulator.

3. The detector of claim 1 , further comprising a waveguide configured to guide the received electromagnetic radiation for incidence upon the first layer and the second layer.

4. The detector of claim 1 , wherein the third layer includes a ferromagnetic material.

5. The detector of claim 1 , wherein the second layer includes a metal or metal alloy having a spin Hall angle between 0.1 and 0.35.

6. The detector of claim 5 , wherein the metal includes at least one of platinum, tungsten, bismuth, or tantalum or the metal alloy includes gold and platinum.

7. The detector of claim 1 , wherein the electromagnetic radiation received at the first layer includes circular or elliptical polarization.

8. The detector of claim 1 , wherein the first layer is strained to a predetermined level by introducing a residual stress via lattice mismatch with a substrate upon which the first layer is formed.

9. The detector of claim 8 , wherein the predetermined level changes the frequency within the range of sub-terahertz or terahertz frequencies at which the first layer injects spin current into the second layer as compared to the first layer in an unstrained state.

10. The detector of claim 9 , wherein the predetermined level is associated with a desired filter range of the frequency within the range of sub-terahertz or terahertz frequencies at which the first layer injects spin current into the second layer.

11. A method of detecting electromagnetic radiation, comprising:

receiving electromagnetic radiation having a frequency within the range of sub-terahertz or terahertz frequencies by an electromagnetic radiation detector, wherein the electromagnetic radiation detector includes a first layer of an antiferromagnetic material (AFM), a second layer in contact with the first layer and including a heavy metal (HM), and a third layer opposite the second layer and in contact with the first layer;

generating an effective field having a direction oriented approximately parallel to an easy axis of a crystal lattice of the antiferromagnetic material and to a direction of propagation of the received electromagnetic radiation; and

generating, within the first layer, a spin current in response to receipt of the electromagnetic radiation;

receiving, by the second layer, the spin current;

generating, within the second layer, a potential difference in response to receipt of the spin current; and

outputting, by an electrical circuit in electrical communication with the second layer, an electrical signal corresponding to the potential difference.

12. The method of claim 11 , wherein the second layer includes a topological insulator.

13. The method of claim 11 , wherein the electromagnetic radiation detector further comprises a waveguide configured to guide the received electromagnetic radiation for incidence upon the first layer and the second layer.

14. The method of claim 11 , wherein the third layer includes a ferromagnetic material.

15. The method of claim 11 , wherein the second layer includes a metal or a metal alloy having a spin Hall angle between 0.1 and 0.35.

16. The method of claim 15 , wherein the metal includes at least one of platinum, tungsten, bismuth, or tantalum or the metal alloy includes gold and platinum.

17. The method of claim 11 , wherein the electromagnetic radiation received at the first layer includes circular or elliptical polarization.

18. The method of claim 11 , wherein the first layer is strained to a predetermined level by introducing a residual stress via lattice mismatch with a substrate upon which the first layer is formed.

19. The method of claim 18 , wherein the predetermined level changes the frequency within the range of sub-terahertz or terahertz frequencies at which the first layer injects spin current into the second layer as compared to the first layer in an unstrained state.

20. The method of claim 19 , wherein the predetermined level is associated with a desired filter range of the frequency within the range of sub-terahertz or terahertz frequencies at which the first layer injects spin current into the second layer.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jul 27, 2023
From: SHI, JING; LI, JUNXUE
To: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
Reel/Frame 064406/0103 →
Continuity (4)
Continuation 17020796 · Sep 14, 2020
Provisional Application 62925427 · Oct 24, 2019
Provisional Application 62914794 · Oct 14, 2019
Related Publication 20230266413A1 · Aug 24, 2023
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