AC VECTOR MAGNETIC ANOMALY DETECTION WITH DIAMOND NITROGEN VACANCIES

• US 20170212190A1
• Filed: 01/21/2016
• Published: 07/27/2017
• Est. Priority Date: 01/21/2016
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: REYNOLDS, Colleen Mary, COAR, David Nelson, DECRISTOFORO, Mary Catherine Chih-Li, EGAN, Laird Nicholas, RUSSO, Jon C.
• Granted Patent: US 10,338,162 B2
• Time in Patent Office: Days
• CPC Class Codes: G01R 33/26 using optical pumping

Abstract

A system for magnetic anomaly detection is described. The system may include a nitrogen vacancy (NV) diamond material comprising a plurality of NV centers. A controller modulates a first code packet and controls a first magnetic field generator to apply a first time varying magnetic field at the NV diamond material based on the modulated first code packet. The controller modulates a second code packet and control a second magnetic field generator to apply a second time varying magnetic field at the NV diamond material based on the modulated second code packet, wherein the first code packet and the second code packet are binary sequences which have a low cross correlation with each other. The controller determines a magnitude and direction of the magnetic field at the NV diamond material, and determines a magnetic vector anomaly based on the determined magnitude and direction of the magnetic field.

Claims

1. A system for magnetic detection, comprising:

a nitrogen vacancy (NV) diamond material comprising a plurality of NV centers;

a magnetic field generator configured to generate a magnetic field;

a radio frequency (RF) excitation source configured to provide RF excitation to the NV diamond material;

an optical excitation source configured to provide optical excitation to the NV diamond material;

an optical detector configured to receive an optical signal emitted by the NV diamond material; and

a controller configured to;

control the magnetic field generator to apply a time varying magnetic field at the NV diamond material,

determine a magnitude and direction of the magnetic field at the NV diamond material based on a received light detection signal from the optical detector, and

determine a magnetic vector anomaly due to an object based on the determined magnitude and direction of the magnetic field according to a frequency dependent attenuation of the time varying magnetic field.

2. The system of claim 1, wherein the object is ferrous.

3. The system of claim 1, wherein the object is non-ferrous.

4. A system for magnetic detection, comprising:

a nitrogen vacancy (NV) diamond material comprising a plurality of NV centers;

a magnetic field generator comprising at least two magnetic field generators including a first magnetic field generator configured to generate a first magnetic field and a second magnetic field generator configured to generate a second magnetic field;

a radio frequency (RF) excitation source configured to provide RF excitation to the NV diamond material;

an optical excitation source configured to provide optical excitation to the NV diamond material;

an optical detector configured to receive an optical signal emitted by the NV diamond material; and

a controller configured to;

modulate a first code packet and control the first magnetic field generator to apply a first time varying magnetic field at the NV diamond material based on the modulated first code packet,

modulate a second code packet and control the second magnetic field generator to apply a second time varying magnetic field at the NV diamond material based on the modulated second code packet, wherein the first code packet and the second code packet are binary sequences which have a low cross correlation with each other, and each of the binary sequences has a good autocorrelation.

5. The system of claim 4, wherein a direction of the first time varying magnetic field at the NV diamond material is different from a direction of the second time varying magnetic field at the NV diamond material.

6. The system of claim 4, wherein the controller is further configure to:

receive first light detection signals from the optical detector based on the optical signal emitted by the NV diamond material based on the first code packet transmitted to the NV diamond material, and receive second light detection signals from the optical detector based on the optical signal emitted by the NV diamond material based on the second code packet transmitted to the NV diamond material simultaneous with the first code packet being transmitted to the NV diamond material;

apply matched filters to the received first and second light detection signals to demodulate the first and second code packets,

determine a magnitude and direction of the first magnetic field and the second magnetic field at the NV diamond material based on the demodulated first and second code packets; and

determine a magnetic vector anomaly based on the determined magnitude and direction of the first magnetic field and the second magnetic field.

7. The system of claim 4, wherein the first and second code packets are modulated by continuous phase modulation.

8. The system of claim 4, wherein the first and second code packets are modulated by MSK frequency modulation.

9. A system for magnetic detection, comprising:

a nitrogen vacancy (NV) diamond material comprising a plurality of NV centers;

a magnetic field generator configured to generate a magnetic field;

a radio frequency (RF) excitation source configured to provide RF excitation to the NV diamond material;

an optical excitation source configured to provide optical excitation to the NV diamond material;

an optical detector configured to receive an optical signal emitted by the NV diamond material; and

a controller configured to;

control the magnetic field generator to apply a time varying magnetic field at the NV diamond material,

determine a magnitude and direction of the magnetic field at the NV diamond material based on a received light detection signal from the optical detector, and

determine a magnetic vector anomaly based on the determined magnitude and direction of the magnetic field.

10. The system of claim 9, wherein the magnetic field generator comprising two or more magnetic field generators including a first magnetic field generator configured to generate a first magnetic field at the NV diamond material in a first direction and a second magnetic field generator configured to generate a second magnetic field at the NV diamond material in a second direction different from the first direction.

11. The system of claim 10, wherein the first direction is orthogonal to the second direction.

12. The system of claim 10, wherein the controller is configured to:

modulate a first code packet and control the first magnetic field generator to apply a first time varying magnetic field at the NV diamond material based on the modulated first code packet, and

modulate a second code packet and control the second magnetic field generator to apply a second time varying magnetic field at the NV diamond material based on the modulated second code packet, wherein the first code packet and the second code packet are binary sequences which have a low cross correlation with each other, and each of the binary sequences has a good autocorrelation.

13. A system for magnetic detection, comprising:

a nitrogen vacancy (NV) diamond material comprising a plurality of NV centers;

a magnetic field generator comprising two or more magnetic field generators including a first magnetic field generator configured to generate a first magnetic field and a second magnetic field generator configured to generate a second magnetic field;

a radio frequency (RF) excitation source configured to provide RF excitation to the NV diamond material;

an optical excitation source configured to provide optical excitation to the NV diamond material;

an optical detector configured to receive an optical signal emitted by the NV diamond material; and

a controller configured to;

control the first magnetic field generator to apply a first time varying magnetic field at the NV diamond material,

control the second magnetic field generator to apply a second time varying magnetic field at the NV diamond material, wherein a direction of the first time varying magnetic field at the NV diamond material is different from a direction of the second time varying magnetic field at the NV diamond material,

determine a magnitude and direction of the first magnetic field and the second magnetic field at the NV diamond material based on the received light detection signal from the optical detector; and

determine a magnetic vector anomaly based on the determined magnitude and direction of the first magnetic field and the second magnetic field.

14. The system of claim 13, wherein the direction of the first magnetic field at the NV diamond material is orthogonal to the direction of the second magnetic field at the NV diamond material.

15. The system of claim 13, wherein the controller is configured to control the RF excitation source and the optical excitation source to provide a sequence of pulses to the NV diamond material.

16. The system of claim 15, wherein the sequence of pulses is a Ramsey sequence.

17. The system of claim 13, wherein the controller is configured to:

modulate a first code packet and control the first magnetic field generator to apply a first time varying magnetic field at the NV diamond material based on the modulated first code packet, and

modulate a second code packet and control the second magnetic field generator to apply a second time varying magnetic field at the NV diamond material based on the modulated second code packet, wherein the first code packet and the second code packet are binary sequences which have a low cross correlation with each other, and each of the binary sequences has as good autocorrelation.

18. A system for magnetic detection, comprising:

a nitrogen vacancy (NV) diamond material comprising a plurality of NV centers;

a magnetic field generator configured to generate a magnetic field;

a radio frequency (RF) excitation source configured to provide RF excitation to the NV diamond material;

an optical excitation source configured to provide optical excitation to the NV diamond material;

an optical detector configured to receive an optical signal emitted by the NV diamond material; and

a controller configured to;

control the magnetic field generator to apply a first magnetic field at the NV diamond material and to apply a second magnetic field at the NV diamond material having a direction different from the first magnetic field;

control the RF excitation source and the optical excitation source to provide a sequence of pulses to the NV diamond material;

receive a light detection signal from the optical detector based on the optical signal emitted by the NV diamond material based on the sequence of pulses;

determine a magnitude and direction of the first magnetic field and the second magnetic field at the NV diamond material based on the received light detection signal from the optical detector; and

determine a magnetic vector anomaly based on the determined magnitude and direction of the first magnetic field and the second magnetic field.

19. The system of claim 18, wherein a direction of the first magnetic field at the NV diamond material is orthogonal to a direction of the second magnetic field at the NV diamond material.

20. The system of claim 18, wherein the sequence of pulses is a Ramsey sequence.

21. The system of claim 18, wherein the controller is configured to:

modulate a first code packet and control the first magnetic field generator to apply a first time varying magnetic field at the NV diamond material based on the modulated first code packet, and

modulate a second code packet and control the second magnetic field generator to apply a second time varying magnetic field at the NV diamond material based on the modulated second code packet, wherein the first code packet and the second code packet are binary sequences which have a low cross correlation with each other, and each of the binary sequences has as good autocorrelation.

22. The system of claim 18, wherein the controller is further configured to identify an object corresponding to the magnetic vector anomaly.

23. A system for magnetic detection, comprising:

a nitrogen vacancy (NV) diamond material comprising a plurality of NV centers;

a magnetic field generator configured to generate a magnetic field;

a radio frequency (RF) excitation source configured to provide RF excitation to the NV diamond material;

an optical excitation source configured to provide optical excitation to the NV diamond material;

an optical detector configured to receive an optical signal emitted by the NV diamond material; and

a control unit for;

controlling the magnetic field generator to apply a time varying magnetic field at the NV diamond material;

determining a magnitude and direction of the magnetic field at the NV diamond material based on a received light detection signal from the optical detector; and

determining a magnetic vector anomaly based on the determined magnitude and direction of the magnetic field.

24. The system of claim 23, wherein the controller is further configured to identify an object corresponding to the magnetic vector anomaly.

25. The system of claim 24, wherein the controller is further configured to identify an object corresponding to the magnetic vector anomaly based on comparing the determined magnetic vector anomaly with magnetic vector anomalies stored in a reference library.

26. A system for magnetic detection, comprising:

a magneto-optical defect center material;

a magnetic field generator comprising at least two magnetic field generators including at least two magnetic field generators including a first magnetic field generator configured to generate a first magnetic field and a second magnetic field generator configured to generate a second magnetic field;

a radio frequency (RF) excitation source configured to provide RF excitation to the magneto-optical defect center material;

an optical excitation source configured to provide optical excitation to the magneto-optical defect center material;

an optical detector configured to receive an optical signal emitted by the magneto-optical defect center material; and

a controller configured to;

modulate a first code packet and control the first magnetic field generator to apply a first time varying magnetic field at the magneto-optical defect center material based on the modulated first code packet,

modulate a second code packet and control the second magnetic field generator to apply a second time varying magnetic field at the magneto-optical defect center material based on the modulated second code packet, wherein the first code packet and the second code packet are binary sequences which have a low cross correlation with each other, and each of the binary sequences has as good autocorrelation.

27. The system of claim 26, wherein a direction of the first time varying magnetic field at the magneto-optical defect center material is different from a direction of the second time varying magnetic field at the magneto-optical defect center material.

28. The system of claim 26, wherein the controller is further configure to:

receive first light detection signals from the optical detector based on the optical signal emitted by the magneto-optical defect center material based on the first code packet transmitted to the magneto-optical defect center material, and receive second light detection signals from the optical detector based on the optical signal emitted by the magneto-optical defect center material based on the second code packet transmitted to the magneto-optical defect center material simultaneous with the first code packet being transmitted to the NV diamond material;

apply matched filters to the received first and second light detection signals to demodulate the first and second code packets,

determine a magnitude and direction of the first magnetic field and the second magnetic field at the magneto-optical defect center material based on the demodulated first and second code packets; and

determine a magnetic vector anomaly based on the determined magnitude and direction of the first magnetic field and the second magnetic field.

29. The system of claim 26, wherein the first and second code packets are modulated by continuous phase modulation.

30. The system of claim 26, wherein the first and second code packets are modulated by MSK frequency modulation.

31. A system for magnetic detection, comprising:

a magneto-optical defect center material;

a magnetic field generator configured to generate a magnetic field;

a radio frequency (RF) excitation source configured to provide RF excitation to the magneto-optical defect center material;

an optical excitation source configured to provide optical excitation to the magneto-optical defect center material;

an optical detector configured to receive an optical signal emitted by the magneto-optical defect center material; and

a controller configured to;

control the magnetic field generator to apply a first magnetic field at the magneto-optical defect center material and to apply a second magnetic field at the magneto-optical defect center material having a direction different from the first magnetic field;

control the RF excitation source and the optical excitation source to provide a sequence of pulses to the magneto-optical defect center material;

receive a light detection signal from the optical detector based on the optical signal emitted by the magneto-optical defect center material based on the sequence of pulses;

determine a magnitude and direction of the first magnetic field and the second magnetic field at the magneto-optical defect center material based on the received light detection signal from the optical detector; and

determine a magnetic vector anomaly based on the determined magnitude and direction of the first magnetic field and the second magnetic field.

32. A system for magnetic detection, comprising:

a magneto-optical defect center material;

a magnetic field generator configured to generate a magnetic field;

a radio frequency (RF) excitation source configured to provide RF excitation to the magneto-optical defect center material;

an optical excitation source configured to provide optical excitation to the magneto-optical defect center material;

an optical detector configured to receive an optical signal emitted by the magneto-optical defect center material; and

a controller configured to;

control the magnetic field generator to apply a time varying magnetic field at the magneto-optical defect center material;

determine a magnitude and direction of the magnetic field at the magneto-optical defect center material based on a received light detection signal from the optical detector; and

determine a magnetic vector anomaly based on the determined magnitude and direction of the magnetic field.

33. A system for magnetic detection, comprising:

a nitrogen vacancy (NV) diamond material comprising a plurality of NV centers;

a magnetic field generator means comprising at least two magnetic field generators including a first magnetic field generator means configured for generating a first magnetic field and a second magnetic field generator mean for generating a second magnetic field;

a radio frequency (RF) excitation means for providing RF excitation to the NV diamond material;

an optical excitation means for providing optical excitation to the NV diamond material;

an optical detection means for receiving an optical signal emitted by the NV diamond material; and

a control means for;

modulating a first code packet and controlling the first magnetic field generator means to apply a first time varying magnetic field at the NV diamond material based on the modulated first code packet,

modulating a second code packet and controlling the second magnetic field generator means to apply a second time varying magnetic field at the NV diamond material, simultaneous with the first time varying magnetic field being applied at the NV diamond material, based on the modulated second code packet, wherein the first code packet and the second code packet are binary sequences which have a low cross correlation with each other, and each of the binary sequences has a good autocorrelation.

34. The system of claim 33, wherein a direction of the first time varying magnetic field at the NV diamond material is different from a direction of the second time varying magnetic field at the NV diamond material.

35. The system of claim 33, wherein the control means is further for:

receiving first light detection signals from the optical detection means based on the optical signal emitted by the NV diamond material based on the first code packet transmitted to the NV diamond material, and receiving second light detection signals from the optical detection means based on the optical signal emitted by the NV diamond material based on the second code packet transmitted to the NV diamond material simultaneous with the first code packet transmitted to the NV diamond material;

applying matched filters to the received first and second light detection signals to demodulate the first and second code packets,

determining a magnitude and direction of the first magnetic field and the second magnetic field at the NV diamond material based on the demodulated first and second code packets; and

determining a magnetic vector anomaly based on the determined magnitude and direction of the first magnetic field and the second magnetic field.

36. The system of claim 33, wherein the first and second code packets are modulated by continuous phase modulation.

37. The system of claim 33, wherein the first and second code packets are modulated by MSK frequency modulation.

38. A system for magnetic detection, comprising:

a nitrogen vacancy (NV) diamond material comprising a plurality of NV centers;

a magnetic field generator means for generating a magnetic field;

a radio frequency (RF) excitation means for providing RF excitation to the NV diamond material;

an optical excitation means for providing optical excitation to the NV diamond material;

an optical detection means for receiving an optical signal emitted by the NV diamond material; and

a control means for;

controlling the magnetic field generator means to apply a first magnetic field at the NV diamond material and to apply a second magnetic field at the NV diamond material having a direction different from the first magnetic field;

controlling the RF excitation means and the optical excitation means to provide a sequence of pulses to the NV diamond material;

receiving a light detection signal from the optical detection means based on the optical signal emitted by the NV diamond material based on the sequence of pulses;

determining a magnitude and direction of the first magnetic field and the second magnetic field at the NV diamond material based on the received light detection signal from the optical detection means; and

determining a magnetic vector anomaly based on the determined magnitude and direction of the first magnetic field and the second magnetic field.

39. A system for magnetic detection, comprising:

a nitrogen vacancy (NV) diamond material comprising a plurality of NV centers;

a magnetic field generator means for generating a magnetic field;

a radio frequency (RF) excitation means of providing RF excitation to the NV diamond material;

an optical excitation means of providing optical excitation to the NV diamond material;

an optical detection means for receiving an optical signal emitted by the NV diamond material; and

a control means for;

controlling the magnetic field generator means to apply a time varying magnetic field at the NV diamond material;

determining a magnitude and direction of the magnetic field at the NV diamond material based on a received light detection signal from the optical detection means; and

determining a magnetic vector anomaly based on the determined magnitude and direction of the magnetic field.