GYROSCOPES BASED ON NITROGEN-VACANCY CENTERS IN DIAMOND

• US 20150090033A1
• Filed: 10/02/2014
• Published: 04/02/2015
• Est. Priority Date: 04/13/2012
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Budker, Dmitry, Ledbetter, Micah, Jensen, Kasper, Jarmola, Andrey
• Granted Patent: US 9,689,679 B2
• Time in Patent Office: Days
• US Class Current: 73/504.05
• CPC Class Codes: G01C 19/58 Turn-sensitive devices without moving masses
• CPC Class Codes: G01C 19/62 with optical pumping
• CPC Class Codes: G01R 33/46 NMR spectroscopy

Abstract

A solid-state gyroscope apparatus based on ensembles of negatively charged nitrogen-vacancy (NV⁻) centers in diamond and methods of detection are provided. In one method, rotation of the NV⁻ symmetry axis will induce Berry phase shifts in the NV⁻ electronic ground-state coherences proportional to the solid angle subtended by the symmetry axis. A second method uses a modified Ramsey scheme where Berry phase shifts in the ¹⁴N hyperfine sublevels are employed.

Claims

1. A method of inertial sensing, comprising:

(a) providing a diamond sensor with a plurality of nitrogen-vacancy centers;

(b) exposing the diamond sensor to a magnetic field along nitrogen-vacancy center axes;

(c) rotating the diamond sensor to generate geometric phase shifts in the nitrogen-vacancy centers;

(d) detecting the geometric phase shifts; and

(e) reading information from the geometric phase shifts.

2. A method as recited in claim 1, wherein said diamond sensor has nitrogen-vacancy centers with a concentration of between 10 and 200 vacancies per million carbon atoms.

3. A method as recited in claim 1, wherein said magnetic field is a field within the range of 9 Gauss and 11 Gauss.

4. A method as recited in claim 1, wherein detection of said geometric phase shifts comprises:

exposing the diamond sensor to 532 nm pump light;

applying a first π

/2 microwave pulse to the diamond sensor;

allowing spins to precess for a time; and

applying a second π

/2 microwave pulse.

5. A method as recited in claim 1, wherein said reading of phase shifts comprises monitoring transmission of infrared light tuned to 1042 nm transition between singlet levels.

6. A method as recited in claim 1, wherein said reading of phase shifts comprises:

illuminating the diamond with a 532-nm pump light; and

monitoring fluorescence of the diamond over time.

7. A method of inertial sensing, comprising:

(a) providing a diamond sensor with a plurality of nitrogen-vacancy centers;

(b) exposing the diamond sensor to a magnetic field;

(c) illuminating the diamond sensor in the magnetic field with a 532-nm light;

(d) applying a first radio frequency pulse at a hyperfine transition frequency initiating the sensor to a state sensitive to rotations;

(e) rotating the diamond sensor to generate geometric phase shifts;

(f) applying a second radio frequency pulse at a hyperfine transition frequency to convert the sensor to a state that can be optically probed; and

(g) reading nuclear spin states.

8. A method as recited in claim 7, wherein said diamond sensor has nitrogen-vacancy centers with a concentration of between 10 and 200 vacancies per million carbon atoms.

9. A method as recited in claim 7, wherein said magnetic field exposure comprises:

exposing the diamond sensor to a field between 400 Gauss and 600 Gauss; and

reducing the magnetic field to 10 Gauss before applying the first radio frequency.

10. A method as recited in claim 9, further comprising ceasing illumination of the diamond sensor before applying the first radio frequency.

11. A method as recited in claim 7, wherein said first radio frequency pulse is a π

/2 pulse resonantly tuned to the hyperfrequency of 5.1 MHz.

12. A method as recited in claim 7, wherein said second radio frequency pulse is a π

/2 pulse resonantly tuned to the hyperfrequency of 5.1 MHz.

13. A method as recited in claim 7, wherein said reading of nuclear spin states comprises:

applying microwave radiation tuned to a 14 N hyperfine transition;

illuminating the diamond with a 532-nm light; and

analyzing fluorescence emitted from the diamond.

14. A method as recited in claim 7, wherein said reading of nuclear spin states comprises:

applying microwave radiation tuned to a 14 N hyperfine transition;

illuminating the diamond with a 532-nm light; and

analyzing infrared absorption of the diamond.

15. A method as recited in claim 7, wherein the nuclear spin states are detected by Optically Detected Magnetic Resonance (ODMR) spectroscopy.

16. A solid state gyroscope apparatus, comprising:

a diamond with a plurality of nitrogen-vacancy centers on a spindle;

a 532-nm light source configured to expose the diamond to light;

a magnetic field source configured to expose the diamond to a magnetic field;

a microwave radiation source configured to expose the diamond to microwave radiation; and

a detector.

17. An apparatus as recited in claim 16, wherein said light source comprises a laser light source.

18. An apparatus as recited in claim 16, further comprising a focusing mirror disposed between the diamond and the light source and the detector.

19. An apparatus as recited in claim 16, wherein said magnetic field source comprises magnetic coils capable of producing magnetic fields from 10 Gauss to 600 Gauss.

20. An apparatus as recited in claim 16, wherein said detector comprises a fluorescence detector.

21. An apparatus as recited in claim 16, wherein said detector comprises an infrared absorption detector.