Wide-field diamond magnetic imaging for high-throughput particle analysis

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Solution Overview

Problem

Current technologies for magnetic particle analysis lack the capability for high-throughput, sensitive measurement of individual magnetic properties, failing to provide comprehensive quality control and analysis needed for diverse applications of magnetic particles.

Innovation Solution

Wide-field diamond magnetic imaging using nitrogen-vacancy (NV) centers in a diamond sensor, which involves applying a magnetic bias field, illuminating NV centers with green light, and applying microwave fields to acquire fluorescence images, allowing for the determination of magnetic susceptibility, remanent magnetization, and coercivity of individual magnetic particles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ensemble measurements such as vibrating sample magnetometry are used, then measurement speed is improved, but measurement precision of single-particle properties deteriorates

Engineering Contradiction:
Improvemeasurement throughputVSAvoidsingle-particle magnetic property measurement
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The invention segments the measurement approach by using an array of nitrogen-vacancy centers in diamond to perform parallel single-particle measurements. Instead of measuring particles one at a time or averaging ensembles, the patent divides the sensing area into multiple NV center locations that can simultaneously detect magnetic fields from multiple particles, achieving both high throughput and single-particle resolution.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces traditional mechanical measurement systems (such as physical manipulation in scanning magnetometry) with an optical detection system based on nitrogen-vacancy centers in diamond. This optical system uses photoluminescence imaging to detect magnetic fields, enabling non-contact, high-speed measurements that maintain single-particle sensitivity while achieving ensemble-level throughput.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If single-particle measurement technologies such as scanning magnetometry are used, then measurement precision is improved, but productivity deteriorates

Engineering Contradiction:
Improvesingle-particle magnetic property measurementVSAvoidmeasurement throughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The invention merges the advantages of single-particle sensitivity with multi-particle throughput by combining an array of nitrogen-vacancy centers into a single integrated sensing platform. Multiple NV centers are embedded in a diamond substrate and imaged simultaneously using photoluminescence microscopy, allowing parallel measurement of many particles while maintaining the precision of single-particle detection.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from one-dimensional or sequential measurement approaches to a two-dimensional array of NV centers that can simultaneously probe multiple particles across a spatial plane. This dimensional expansion enables parallel processing of particle data, dramatically increasing throughput while preserving single-particle measurement capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If conventional magnetic particle analysis tools are used, then device complexity is reduced, but adaptability to different magnetic properties deteriorates

Engineering Contradiction:
Improveanalysis of disparate magnetic propertiesVSAvoidmeasurement system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The nitrogen-vacancy center in diamond serves as a universal sensor that can detect various magnetic properties including magnetic moment, susceptibility, anisotropy, and relaxation dynamics. The same NV center array system can measure different particle types (superparamagnetic, ferromagnetic, ferrimagnetic) and different property types without requiring fundamental changes to the measurement platform, achieving multi-functionality through the inherent versatility of NV center magnetometry.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enables high-precision, high-throughput analysis of thousands of magnetic particles simultaneously, providing detailed quantitative measurements of magnetic properties, including remanent magnetization and coercivity, suitable for industrial quality control and diverse applications.

Implementation Method 1

illuminating nitrogen-vacancy (NV) centers in the sensing surface with green light

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 2

acquire an image of NV center fluorescence emitted from the sensing surface

Methodology Applied
Scientific EffectOptical detection: Photoelectric Effect

Implementation Method 3

applying a microwave field to the sensing surface with frequency near one of the NV center electronic spin resonance (ESR) transitions

Methodology Applied
Scientific EffectElectronic spin resonance: Electron Paramagnetic Resonance

Implementation Method 4

applying a magnetic bias field on the plurality of magnetic particles positioned on the sensing surface

Methodology Applied
Scientific EffectMagnetic force: Lorentz Force

Data Source

PatentEP3529595B1Methods and apparatus for magnetic particle analysis using wide-field diamond magnetic imaging
Publication Date: 2023.05.31 QUANTUM DIAMOND TECHNOLOGIES INC
  • EP3529595B1 patent drawingFigure 1
  • EP3529595B1 patent drawingFigure 2
  • EP3529595B1 patent drawingFigure 3

AI summary

The present application discloses methods and apparatus for measuring the arbitrary magnetic response of many individual magnetic particles at once, using a plurality of magnetic images of the magnetic particles acquired over a range of magnetic conditions.