Diamond 13C Hyperpolarisation via Long-Range Dipolar Interaction

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Solution Overview

Problem

Current methods for hyperpolarizing 13C nuclear spins in diamonds are limited in achieving high polarization degrees and are not suitable for long-range interactions, which restricts their application in magnetic resonance applications and imaging agents.

Innovation Solution

A method involving optical pumping of colour centre electron spins in diamonds followed by a dynamic nuclear polarization protocol to transfer polarization to 13C nuclear spins via long-range interactions, such as coherent dipolar interactions, allowing for higher polarization degrees and broader applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If short-lived colour centre spin states are used for polarisation transfer, then the polarisation can be transferred quickly, but the interaction range is limited to short distances and cannot reach nuclei far away

Engineering Contradiction:
Improvepolarisation transfer speedVSAvoidinteraction range
Core Design Contradiction:
SpeedVSLength of stationary object

Solution Approach 1:

The patent changes the fundamental parameter of the colour centre spin state from short-lived to long-lived. Specifically, it uses ground state or metastable triplet states with coherence times exceeding microseconds, which enables the dipolar interaction to effectively reach nuclear spins at distances greater than 5 nm while maintaining sufficient coupling strength for polarisation transfer

Inventive Principle:
Principle #35Parameter changes

2Productivity

If short-range contact interaction is used for polarisation transfer, then the transfer efficiency is high, but the polarisation cannot diffuse to nuclei further away

Engineering Contradiction:
Improvepolarisation transfer efficiencyVSAvoidpolarisation diffusion range
Core Design Contradiction:
ProductivityVSLength of stationary object

Solution Approach 1:

The patent introduces a long-lived colour centre spin state as an intermediary that mediates the polarisation transfer from electrons to distant nuclear spins. This intermediary maintains quantum coherence over extended periods, allowing the dipolar interaction to bridge the gap between the colour centre and nuclear spins at distances greater than 5 nm, thus extending the effective range while maintaining transfer efficiency

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If very short coherence time of colour centres is used, then the system is simple, but the polarisation cannot be transferred via long-range interactions

Engineering Contradiction:
Improvesystem simplicityVSAvoidinteraction distance
Core Design Contradiction:
Device complexityVSLength of stationary object

Solution Approach 1:

The patent changes the coherence time parameter of the colour centre from very short (nanosecond scale) to long-lived (microsecond scale or longer). This is achieved by selecting specific colour centres with ground state or metastable triplet states that possess inherently long coherence times, thereby enabling long-range dipolar interactions without introducing additional system complexity

Inventive Principle:
Principle #35Parameter changes

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 higher and faster hyperpolarization of 13C nuclear spins in diamonds, enabling improved magnetic resonance imaging, medical imaging, and quantum information processing with enhanced signal density and coherence times.

Implementation Method 1

The electron spin of a colour centre in a diamond can be optically polarised

Methodology Applied
Scientific EffectOptical pumping:

Implementation Method 2

The polarisation is transferred to 13C nuclear spins via dipolar long-range interaction

Methodology Applied
Scientific EffectDipolar interaction:

Implementation Method 3

by applying electromagnetic fields analogous to the Hartmann-Hahn matching condition

Methodology Applied
Scientific EffectHartmann-Hahn matching condition:

Data Source

PatentEP2984499B1Method for the hyperpolarisation of nuclear spins in a diamond via a long-range interaction
Publication Date: 2020.09.02 UNIV ULM
  • EP2984499B1 patent drawingFigure 1a~1b
  • EP2984499B1 patent drawingFigure 2
  • EP2984499B1 patent drawingFigure 3

AI summary

The invention concerns a method for the hyperpolarisation of 13C nuclear spin in a diamond, comprising an optical pumping step, in which colour centre electron spins in the diamond are optically pumped. The method further comprises a transfer step in which the polarisation of a long-lived state of the colour centre electron spins is transferred to 13C nuclear spins in the diamond via a long-range interaction.