METHOD FOR HYPER-POLARIZING NUCLEAR SPINS AT ARBITRARY MAGNETIC FIELDS

• US 20160161583A1
• Filed: 12/08/2015
• Published: 06/09/2016
• Est. Priority Date: 12/08/2014
• Status: Active Grant

• Current Assignee: City College of New York
• Original Assignee: City College of New York
• Inventors: Meriles, Carlos A., Pagliero, Daniela, Laraoui, Abdelghani
• Granted Patent: US 10,180,479 B2
• Time in Patent Office: Days
• CPC Class Codes: G01N 24/08 by using nuclear magnetic resonance G01N24/12 takes precedence
• CPC Class Codes: G01R 33/282 Means specially adapted for hyperpolarisation or for hyperpolarised contrast agents, e.g. for the generation of hyperpolarised gases using optical pumping cells, for storing hyperpolarised contrast agents or for the determination of the polarisation of a hyperpolarised contrast agent
• CPC Class Codes: G01R 33/5605 by transferring coherence or polarization from a spin species to another, e.g. creating magnetization transfer contrast [MTC], polarization transfer using nuclear Overhauser enhancement [NOE]

Abstract

A method of dynamically polarizing the nuclear spin host of nitrogen-vacancy (NV) centers in diamond is provided. The method uses optical, microwave and radio-frequency pulses to recursively transfer spin polarization from the NV electronic spin. Nitrogen nuclear spin initialization approaching 80% at room temperature is demonstrated both in ensemble and single NV centers without relying on level anti-crossings. This makes the method applicable at arbitrary magnetic fields.

Claims

1. A method for polarizing spins, the method comprising steps of:

exposing a substrate to a magnetic field, the substrate comprising a surface with a plurality of ¹⁴N spin defect centers within 25 nm of the surface;

treating the plurality of ¹⁴N spin defect centers with electromagnetic waves according to a protocol to produce polarized spins in the ¹⁴N spin defect centers, wherein the protocol comprises sequential pulses of;

a first visible light pulse (p0);

a first microwave pulse (mw1);

a first radio frequency pulse (rf1);

a second microwave pulse (mw2);

a second radio frequency pulse (rf2).

2. The method as recited in claim 1, wherein the step of treating is repeated at least four times within one second.

3. The method as recited in claim 1, wherein the step of treating is repeated at least six times within one second.

4. The method as recited in claim 1, wherein the substrate is a diamond crystal substrate.

5. The method as recited in claim 1, wherein the first visible light pulse (p0) has a wavelength between 500 nm and 637 nm.

6. The method as recited in claim 1, wherein the first microwave pulse (mw1) and the second microwave pulse (mw2) each has a frequency between 10 MHz and 300 GHz.

7. The method as recited in claim 1, wherein the first radio frequency pulse (rf1) and the second radio frequency pulse (rf2) each has a frequency between 10 kHz and 100 MHz.

8. The method as recited in claim 1, wherein the protocol is a spin swapping protocol such that the protocol consists of the first visible light pulse (p0), the first microwave pulse (mw1), the first radio frequency pulse (rf1), the a second microwave pulse (mw2) and the second radio frequency pulse (rf2).

9. The method as recited in claim 1, further comprising introducing an analyte to the surface of the substrate.

10. The method as recited in claim 1, wherein the protocol is a population trapping protocol such that the protocol further comprises:

a second visible light pulse (p1) performed after the first radio frequency pulse (rf1) and before the second microwave pulse (mw2);

a third visible light pulse (p2) performed after the second radio frequency pulse (rf2).

11. The method as recited in claim 10, wherein the population trapping protocol consists of the first visible light pulse (p0), the first microwave pulse (mw1), the first radio frequency pulse (rf1), the second visible light pulse (p1), the second microwave pulse (mw2), the second radio frequency pulse (rf2) and the third visible light pulse (p2).

12. The method as recited in claim 11, wherein the first visible light pulse (p0), the second visible light pulse (p1) and the third visible light pulse (p2) each has a wavelength between 500 nm and 637 nm.

13. The method as recited in claim 11, wherein the method is performed at a temperature of 25°

C.±

5°

C.

14. A method for polarizing spins, the method comprising steps of:

exposing a substrate to a magnetic field, the substrate comprising a surface with a plurality of ¹⁴N spin defect centers within 25 nm of the surface;

treating the plurality of ¹⁴N spin defect centers with electromagnetic waves according to a protocol to produce polarized spins in the ¹⁴N spin defect centers, wherein the protocol comprises sequential pulses of;

a first visible light pulse (p0) with a wavelength between 500 nm and 637 nm;

a first microwave pulse (mw1) with a first microwave frequency between 10 MHz and 300 GHz;

a first radio frequency pulse (rf1) with a first radio frequency between 10 kHz and 100 MHz;

a second microwave pulse (mw2) with a second microwave frequency between 10 MHz and 300 GHz;

a second radio frequency pulse (r12) with a second radio frequency between 10 kHz and 100 MHz.

15. A method for polarizing spins, the method comprising steps of:

introducing an analyte to a surface of a substrate comprising a plurality of ¹⁴N spin defect centers implanted within 25 nm of the surface;

exposing the ¹⁴N spin defect centers to a magnetic field while the analyte is proximate the surface;

treating the plurality of ¹⁴N spin defect centers with electromagnetic waves according to a protocol to produce polarized spins in the spin defect centers, wherein the protocol comprises sequential pulses of;

a first visible light pulse (p0);

a first microwave pulse (mw1);

a first radio frequency pulse (rf1);

a second microwave pulse (mw2);

a second radio frequency pulse (r12);

permitting the polarized spins in the ¹⁴N spin defect centers to induce spin polarization in the analyte.

16. The method as recited in claim 15, wherein the polarized spins are induced in the analyte by first transferring the polarized spin from the ¹⁴N spin defect centers to a ¹³C intermediary and thereafter transferring the polarized spin from the ¹³C intermediary to the analyte.

17. The method as recited in claim 15, wherein the ¹³C intermediary is disposed within fifty nm of the surface.

18. The method as recited in claim 15, wherein the protocol is a spin swapping protocol such that the protocol consists of the first visible light pulse (p0), the first microwave pulse (mw1), the first radio frequency pulse (rf1), the a second microwave pulse (mw2) and the second radio frequency pulse (rf2).

19. The method as recited in claim 15, wherein the protocol is a population trapping protocol such that the protocol further comprises:

a second visible light pulse (p1) performed after the first radio frequency pulse (rf1) and before the second microwave pulse (mw2);

a third visible light pulse (p2) performed after the second radio frequency pulse (r12).

20. The method as recited in claim 19, wherein the population trapping protocol consists of the first visible light pulse (p0), the first microwave pulse (mw1), the first radio frequency pulse (rf1), the second visible light pulse (p1), the second microwave pulse (mw2), the second radio frequency pulse (rf2) and the third visible light pulse (p2).