Apparatus and method for high sensitivity magnetometry measurement and signal processing in a magnetic detection system

• US 9,557,391 B2
• Filed: 01/21/2016
• Issued: 01/31/2017
• Est. Priority Date: 01/23/2015
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Egan, Laird Nicholas, Coar, David Nelson, Russo, Jon C.
• Primary Examiner(s): PATIDAR, JAY M
• Application Number:
  US15/003,590
• Publication Number:
  US 20160216340A1
• Time in Patent Office: 376 Days
• Field of Search: 324/244.1
• US Class Current: 1/1
• CPC Class Codes: G01N 21/63 optically excited
• CPC Class Codes: G01N 22/00 Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more G01N3/00 - G01N17/00, G01N24/00 take precedence
• CPC Class Codes: G01R 33/032 using magneto-optic devices, e.g. Faraday or Cotton-Mouton effect

Abstract

A system for magnetic detection may include a nitrogen vacancy (NV) diamond material, a radio frequency (RF) excitation source, an optical excitation source, an optical detector, a magnetic field generator, and a controller. The controller may control the excitation sources to apply a first pulse sequence. The controller may receive a first light detection signal due to the first pulse sequence, measure first and second values of the first light detection signal at first and second reference periods, and compute a first measurement. The controller may further control the excitation sources to apply a second pulse sequence, receive a second light detection signal due to the second pulse sequence, measure first and second values of the second light detection signal at first and second reference periods, and compute a second measurement. The first and second measurements may be based on high and low resonance frequencies of the NV diamond material.

Claims

1. A system for magnetic detection, comprising:

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

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;

a magnetic field generator configured to generate a magnetic field applied to the NV diamond material; and

a controller configured to;

control the optical excitation source and the RF excitation source to apply a first pulse sequence comprising two optical excitation pulses and two RF excitation pulses to the NV diamond material;

receive a first light detection signal from the optical detector based on an optical signal emitted by the NV diamond material due to the first pulse sequence;

measure a first value of the first light detection signal at a first reference period, the first reference period being before a period of the first light detection signal associated with the two RF excitation pulses of the first pulse sequence provided to the NV diamond material;

measure a second value of the first light detection signal at a second reference period, the second reference period being after the period of the first light detection signal associated with the two RF excitation pulses of the first pulse sequence provided to the NV diamond material;

compute a first measurement based on the measured first and second values of the first light detection signal;

control the optical excitation source and the RF excitation source to apply a second pulse sequence comprising two optical excitation pulses and two RF excitation pulses to the NV diamond material;

receive a second light detection signal from the optical detector based on an optical signal emitted by the NV diamond material due to the second pulse sequence;

measure a first value of the second light detection signal at a first reference period, the first reference period being before a period of the second light detection signal associated with the two RF excitation pulses of the second pulse sequence provided to the NV diamond material;

measure a second value of the second light detection signal at a second reference period, the second reference period being after the period of the second light detection signal associated with the two RF excitation pulses of the second pulse sequence provided to the NV diamond material; and

compute a second measurement based on the measured first and second values of the second light detection signal,

wherein the first measurement is based on a high resonance frequency of the NV diamond material, and

wherein the second measurement is based on a low resonance frequency of the NV diamond material.

2. The system of claim 1, wherein the high resonance frequency and the low resonance frequency are resonance frequencies associated with an axis of an NV center of the NV diamond material.

3. The system of claim 1, wherein the controller is further configured to compute a change in an external magnetic field acting on the NV diamond material based on the first and second measurements.

4. The system of claim 1, wherein the two RF excitation pulses of the first pulse sequence are applied at a frequency detuned from the high resonance frequency of the NV diamond material.

5. The system of claim 1, wherein the two RF excitation pulses of the second pulse sequence are applied at a frequency detuned from the low resonance frequency of the NV diamond material.

6. The system of claim 1, wherein the RF excitation source is a microwave antenna.

7. The system of claim 1, wherein the controller is configured to apply one of the two optical excitation pulses, followed by the two RF excitation pulses, and followed by the other of the two optical excitation pulses during each of the first pulse sequence and the second pulse sequence.

8. The system of claim 1, wherein the controller is further configured to measure a third value of the first light detection signal at a signal period, the signal period being after the first reference period and before the second reference period of the first light detection signal.

9. The system of claim 8, wherein the controller is further configured to compute the first measurement based on a difference between the average of the first and second values and the third value of the first light detection signal.

10. A system for magnetic detection, comprising:

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

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;

a magnetic field generator configured to generate a magnetic field applied to the NV diamond material; and

a controller configured to;

control the optical excitation source and the RF excitation source to apply a pulse sequence comprising two optical excitation pulses and at least one RF excitation pulse to the NV diamond material;

receive a light detection signal from the optical detector based on an optical signal emitted by the NV diamond material due to the pulse sequence;

measure a first value of the light detection signal at a first reference period, the first reference period being before a period of the light detection signal associated with the at least one RF excitation pulse provided to the NV diamond material;

measure a second value of the light detection signal at a second reference period, the second reference period being after the period of the light detection signal associated with the at least one RF excitation pulse provided to the NV diamond material; and

compute a measurement signal based on the measured first and second values.

11. The system of claim 10, wherein the controller is further configured to measure the first value and the second value based on an average of values of the light detection signal within the first reference period and the second reference period.

12. The system of claim 10, wherein the controller is further configured to compute the measurement signal based on the average of the first value and the second value.

13. The system of claim 10, wherein the controller is further configured to measure a third value of the light detection signal at a signal period, the signal period being after the first reference period and before the second reference period.

14. The system of claim 13, wherein the controller is further configured to compute the measurement signal based on a difference between the average of the first and second values and the third value.

15. The system of claim 10, wherein the first reference period is associated with one of the two optical excitation pulses and the second reference period is associated with the other of the two optical excitation pulses.

16. A system for magnetic detection, comprising:

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

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;

a magnetic field generator configured to generate a magnetic field applied to the NV diamond material; and

a controller configured to;

control the optical excitation source and the RF excitation source to apply a first pulse sequence comprising two optical excitation pulses and two RF excitation pulses to the NV diamond material;

receive a first light detection signal from the optical detector based on an optical signal emitted by the NV diamond material due to the first pulse sequence;

compute a first measurement based on the first light detection signal;

control the optical excitation source and the RF excitation source to apply a second pulse sequence comprising two optical excitation pulses and two RF excitation pulses to the NV diamond material;

receive a second light detection signal from the optical detector based on an optical signal emitted by the NV diamond material due to the second pulse sequence; and

compute a second measurement based on the second light detection signal,

wherein the first measurement is based on a high resonance frequency of the NV diamond material, and

wherein the second measurement is based on a low resonance frequency of the NV diamond material.

17. The system of claim 16, wherein the high resonance frequency and the low resonance frequency are resonance frequencies associated with an axis of an NV center of the NV diamond material.

18. The system of claim 16, wherein the two RF excitation pulses of the first pulse sequence are applied at a frequency detuned from the high resonance frequency of the NV diamond material.

19. The system of claim 16, wherein the two RF excitation pulses of the second pulse sequence are applied at a frequency detuned from the low resonance frequency of the NV diamond material.

20. The system of claim 16, wherein the controller is further configured to compute a change in an external magnetic field acting on the NV diamond material based on the first and second measurements.