Method for trapping vacancies in a crystal lattice

Patent metadata

Field	Value
Publication number	US-10934635-B2
Application number	US-201615740340-A
Country	US
Kind code	B2
Filing date	Jul 1, 2016
Priority date	Jul 3, 2015
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

There is provided a method of fabricating a trapped vacancy in a crystal lattice of a target comprising: positioning the target in a laser system, the target containing vacancy trapping elements within the crystal lattice; modifying the crystal lattice within the target by using a laser to generate a lattice vacancy; and annealing the target to cause the lattice vacancy to migrate and be captured by a vacancy trapping element to form the trapped vacancy in the crystal lattice.

First claim

The invention claimed is:

1. A method of fabricating a trapped vacancy in a crystal lattice of a target comprising:
positioning the target in a laser system comprising a laser, the target containing vacancy trapping elements within the crystal lattice;
using a pulsed laser beam produced the laser to create a lattice vacancy in the crystal lattice within the target; and
annealing the target to cause the lattice vacancy to migrate and be captured by a vacancy trapping element to form the trapped vacancy in the crystal lattice,
wherein using the pulsed laser beam produced by the laser to create the lattice vacancy comprises:
determining a position for the lattice vacancy within the crystal lattice;
focusing the pulsed laser beam at the determined position within the crystal lattice;
selecting a pulse energy of the pulsed laser beam that causes nonlinear multi-photon absorption by the crystal lattice and creates the lattice vacancy; and
operating the laser to provide the pulse energy within an energy range to create the lattice vacancy within the crystal lattice only within a localized volume of width less than 1 micrometer.

2. The method of claim 1 wherein the laser is operated at a central wavelength such that an absorbed photon has energy that is less than a bandgap of the target.

3. The method of claim 1 wherein the pulse energy of the pulsed laser beam entering the target is in a range between 5 nJ and 15 nJ.

4. The method of claim 1 wherein the vacancy trapping elements are present at a concentration of less than 1 part per million.

5. The method of claim 1 wherein the vacancy trapping element is nitrogen; or wherein the vacancy trapping element is silicon; or wherein the vacancy trapping element is germanium.

6. The method of claim 1 wherein the vacancy trapping elements are deposited during fabrication of the target.

7. The method of claim 1 wherein the trapped vacancy forms part of a colour centre.

8. The method of claim 1 further comprising modifying a wavefront of the pulsed laser beam to cancel aberrations in the pulsed laser beam caused by a refractive index of the target.

9. The method of claim 1 wherein the method includes the step of selecting the pulse energy of the laser relative to a modification threshold of the target in order to reduce an effective beam area for modifying the crystal lattice.

10. The method of claim 1 wherein a modified region of the crystal lattice has a size of less than 200 nm.

11. The method of claim 1 wherein the target is diamond.

12. The method of claim 1 wherein the target is one of: silicon carbide or silicon.

13. The method of claim 1 wherein the annealing comprises heating the target to between 800-1400° C. for a period of 15 minutes to 24 hours.

14. The method of claim 1 wherein the method further comprises forming a two-dimensional or three-dimensional array or pattern of trapped vacancies in the crystal lattice of the target.

15. The method of claim 1 wherein the method is a production step in fabrication of a sensor.

16. The method of claim 1 wherein the method is a production step in fabrication of a quantum component.

17. The method of claim 1 wherein a pulse duration is shorter than a characteristic timescale for thermal diffusion in the target.

18. The method of claim 1 wherein the laser is a picosecond or femtosecond laser.

19. The method of claim 1 , wherein using the pulsed laser beam produced the laser to create the lattice vacancy in the crystal lattice within the target causes fourth-order or higher nonlinear multi-photon absorption in the crystal lattice.

20. The method of claim 1 wherein the method further comprises controlling laser operation so that the target is free of damage in a region around the trapped vacancy following annealing.

21. The method of claim 1 wherein using the pulsed laser beam produced the laser to create the lattice vacancy in the crystal lattice within the target comprises modifying the crystal lattice selectively at a depth of greater than 5 microns from a surface of the target.

22. The method of claim 1 wherein using the pulsed laser beam produced the laser to create the lattice vacancy in the crystal lattice within the target comprises modifying the lattice so as to engineer a strain field about at least one specific trapped vacancy in order to modify its properties.

23. The method of claim 1 wherein a target surface is not affected or modified.

24. The method of claim 1 wherein optical properties of the target remain unchanged except where the trapped vacancy is fabricated.

25. The method of claim 1 wherein annealing the target causes healing of lattice vacancies which are not trapped.

26. A method of fabricating a trapped vacancy in a crystal lattice of a target comprising:
positioning the target in a laser system comprising a laser, the target containing vacancy trapping elements within the crystal lattice;
using a pulsed laser beam produced the laser to create a lattice vacancy in the crystal lattice within the target; and
annealing the target to cause the lattice vacancy to migrate and be captured by a vacancy trapping element to form the trapped vacancy in the crystal lattice,
wherein using the pulsed laser beam produced the laser to create a lattice vacancy in the crystal lattice within the target comprises:
determining a position for the lattice vacancy within the crystal lattice;
focusing the pulsed laser beam at the determined position within the crystal lattice;
selecting a pulse energy of the pulsed laser beam that causes nonlinear multi-photon absorption by the crystal lattice and creates the lattice vacancy; and
operating the laser to provide the pulse energy within an energy range to create the lattice vacancy within the crystal lattice only within a localized volume of width less than 1 micrometer,
wherein the laser is operated at a central wavelength such that an absorbed photon has an energy that is less than a bandgap of the target.

Assignees

• Univ Oxford Innovation Ltd

Inventors

• Booth Martin James
• Salter Patrick
• Smith Jason
• Chen Yu-Chen

Classifications

• H10P14/6542 Primary

  by using coherent radiation, e.g. using a laser · CPC title

• C30B29/04 Primary

  Diamond · CPC title

• C30B33/02

  Heat treatment (C30B33/04, C30B33/06 take precedence) · CPC title

• C01B32/28

  After-treatment, e.g. purification, irradiation, separation or recovery · CPC title

• C30B33/04 Primary

  using electric or magnetic fields or particle radiation · CPC title