Gyroscopes based on nitrogen-vacancy centers in diamond
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 14 N hyperfine sublevels are employed.
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.