Integrated Microwave Antenna for Spin Defect Probe

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Solution Overview

Problem

Current technologies face challenges in measuring weak magnetic fields with high spatial resolution at the nanoscale, which is crucial for imaging stray fields from small ferromagnetic structures and studying novel materials, due to insufficient coupling of microwave fields to spin defects in scanning probe microscopes.

Innovation Solution

A sensor device with a probe containing a spin defect, such as an NV center in diamond, integrated with a microwave antenna positioned close to the spin defect, allowing efficient coupling of microwave fields and enabling high-resolution imaging of magnetic or electric fields by using a scanning probe microscope.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an external microwave antenna is used to couple microwave fields to the spin defect, then the sensor device can perform ODMR experiments, but the positioning and calibration of the antenna becomes complex and time-consuming

Engineering Contradiction:
Improvespatial resolution of magnetic field imagingVSAvoidantenna positioning and calibration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the microwave antenna and the spin defect probe into a single integrated sensor device structure. The antenna is positioned at a defined minimal distance (less than 500 micrometers, preferably less than 200 micrometers) from the spin defect, eliminating the need for separate positioning and calibration procedures. This integration directly resolves the technical contradiction by maintaining measurement precision while reducing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If the microwave antenna is positioned at a larger distance from the spin defect, then the device structure becomes simpler, but the coupling efficiency of microwave fields to the spin defect decreases

Engineering Contradiction:
Improvedevice structure simplicityVSAvoidmicrowave field coupling efficiency
Core Design Contradiction:
Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the distance parameter between the microwave antenna and the spin defect to achieve minimal distance (less than 500 micrometers, preferably less than 200 micrometers). This parameter optimization ensures efficient microwave field coupling while maintaining a practical and manufacturable device structure, resolving the contradiction between ease of manufacture and coupling efficiency.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the probe is scanned over the sample surface, then high spatial resolution imaging is achieved, but the positioning accuracy and stability of the probe becomes more challenging

Engineering Contradiction:
Improvespatial resolution of imagingVSAvoidprobe positioning accuracy and stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The integration of the microwave antenna and spin defect probe into a single rigid structure ensures that their relative positions remain fixed during scanning operations. This structural integration maintains probe positioning accuracy and stability while enabling high spatial resolution imaging through sample surface scanning, resolving the contradiction between measurement precision and reliability.

Inventive Principle:
Principle #5Merging (Combining)

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 configuration allows for robust and efficient coupling of microwave fields to spin defects, enhancing the spatial resolution of magnetic field imaging and reducing the complexity of antenna positioning, thereby improving the ability to measure weak magnetic fields with high precision.

Implementation Method 1

an integrated microwave antenna arranged at a minimal distance of less than 500 micrometers from the spin defect

Methodology Applied
Scientific EffectMicrowave field coupling: Electromagnetic Induction

Implementation Method 2

by carrying out optically detected magnetic resonance (ODMR) experiments on the spin defect

Methodology Applied
Scientific EffectOptically detected magnetic resonance: Absorption (EM radiation)

Implementation Method 3

configured for imaging properties that may influence a spin state of the spin defect, in particular of magnetic or electric fields

Methodology Applied
Scientific EffectMagnetic field interaction: Magnetic Field

Data Source

PatentEP3596483B1Scanning sensor comprising a spin defect
Publication Date: 2022.04.20 ETH ZURICH
  • EP3596483B1 patent drawingFigure 1(a)~3
  • EP3596483B1 patent drawingFigure 4~6
  • EP3596483B1 patent drawingFigure 7

AI summary

A sensor device comprises a carrier (10), a force feedback sensor (20), and a probe (40) containing a spin defect (46), the probe being connected to the force feedback sensor either directly or indirectly via a handle structure (30). In order to couple the spin defect to a microwave field in an efficient and robust manner, the sensor device comprises an integrated microwave antenna (50) arranged at a distance of less than 500 micrometers from the spin defect. The sensor device can be configured as a self-contained exchangeable cartridge that can easily be mounted in a sensor mount of a scanning probe microscope.