Orientation-Independent Hyperpolarization of Diamond Particles

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Solution Overview

Problem

Conventional Dynamic Nuclear Polarization (DNP) techniques are ineffective for diamond powders due to the strong orientational dependence of spin-1 Nitrogen Vacancy (NV) centers, leading to inhomogeneously broadened electronic linewidths, which limits the ability to achieve high bulk nuclear polarization comparable to single crystals.

Innovation Solution

A low-field optical DNP technique that polarizes NV electrons independently of the magnetic field, allowing for orientation-independent polarization transfer from diamond particles to external nuclear spins, utilizing a mechanical shuttle apparatus and microwave irradiation to achieve high bulk 13C polarization in diamond powders.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If conventional DNP techniques are used on diamond powders, then the process can be applied to powdered form with large surface area, but the inhomogeneously broadened electronic linewidth prevents effective polarization transfer

Engineering Contradiction:

Improvesurface areaVSAvoidelectronic linewidth

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent applies dynamic nuclear polarization by modulating the electron spin resonance frequency through magnetic field cycling. The magnetic field is dynamically varied to track the inhomogeneously broadened NV center resonance, enabling effective polarization transfer across the broadened linewidth that static field methods cannot achieve.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the magnetic field strength parameter dynamically during the DNP process. By cycling the magnetic field between different strengths, the method tracks the broadened NV center resonance profile, allowing polarization transfer to occur across the entire inhomogeneously broadened linewidth rather than at a single fixed frequency.

Inventive Principle:

Principle #35Parameter changes

2Area of stationary object

If diamond is used in powdered form to increase contact surface area, then the surface area increases by orders of magnitude, but the orientational dependence of NV centers causes inhomogeneous broadening

Engineering Contradiction:

Improvecontact surface areaVSAvoidorientational uniformity

Core Design Contradiction:

Area of stationary objectVSStability of the object's composition

Solution Approach 1:

The patent creates a universal DNP method that works for diamond particles regardless of their orientation. By dynamically cycling the magnetic field to track the NV center resonance, the method achieves effective polarization transfer for particles with any orientation, making the technique universally applicable to powdered diamond rather than requiring single-crystal orientation control.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The magnetic field is dynamically modulated to adapt to the orientational distribution of NV centers in powdered diamond. This dynamic adjustment allows the system to effectively address NV centers with various orientations simultaneously, overcoming the limitation of fixed-orientation methods.

Inventive Principle:

Principle #15Dynamics

3Manufacturing precision

If single crystal diamond is used, then the electronic linewidth remains narrow with good orientation control, but the surface area of contact to external liquid is very limited

Engineering Contradiction:

Improveelectronic linewidthVSAvoidsurface area

Core Design Contradiction:

Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The patent achieves the polarization transfer efficiency of single crystals by using powdered diamond particles that replicate the NV center properties. The dynamic field tracking method effectively copies the successful single-crystal DNP approach and adapts it to work with the inhomogeneously broadened linewidth characteristic of powdered samples.

Inventive Principle:

Principle #26Copying

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method achieves high bulk 13C polarization comparable to single crystals, with a 31000-fold enhancement over previous nanodiamond hyperpolarization techniques, enabling rapid polarization buildup and on-demand control of hyperpolarization direction, suitable for applications in magnetic resonance imaging and biosensing.

Implementation Method 1

the electronic spin corresponding to the diamond Nitrogen Vacancy (NV) center is optically polarizable to ≈99% at room temperature

Methodology Applied

Scientific EffectOptical polarization: Photoelectric Effect

Implementation Method 2

Dynamic nuclear polarization (DNP)—the ability to employ electron spins to enhance the polarization of, and hence signal from, nuclear spins

Methodology Applied

Scientific EffectDynamic nuclear polarization (DNP): Electromagnetic Induction

Implementation Method 3

A mechanical shuttle apparatus moves a sample of diamond particles through a magnetic field gradient

Methodology Applied

Scientific EffectMagnetic field gradient separation: Magnetic Field

Data Source

PatentUS12017919B2Orientation independent, room temperature, hyperpolarization of diamond nano- and micro-particles

Publication Date: 2024.06.25 RES FOUND THE CITY UNIV OF NEW YORK

AI summary

A method of hyperpolarizing diamond particles includes applying a laser to a sample of the diamond particles, irradiating the diamond particles with a sweeping microwave to cause diamond polarization, shuttling the diamond particles through a magnetic field to detect 13C nuclei in the diamond particles, and relaying the diamond polarization to nuclear spins to one of a surrounding solid or fluid.