Diamond Waveguide NV Center Sensor for Magnetic Field Detection

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Solution Overview

Problem

Existing magnetic field sensors require significant equipment and resources for signal generation and readout, especially when measuring spatial field distributions or time profiles, limiting their sensitivity and spatial resolution.

Innovation Solution

A compact sensor with a diamond waveguide and NV centers on a substrate, using microwave radiation to excite electronic transitions and detect magnetic fields optically, reducing the need for external components and enabling high sensitivity and spatial resolution without cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional magnetic field sensors are used, then magnetic field measurement is possible, but high equipment requirements and complex readout systems are needed

Engineering Contradiction:
Improvemagnetic field detection capabilityVSAvoidequipment requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces conventional magnetic field sensing mechanisms with diamond NV centers that detect magnetic fields through optical means. The NV center's spin state, influenced by magnetic fields, is read out optically via photoluminescence, eliminating the need for complex electromagnetic sensing equipment and replacing mechanical/electromagnetic systems with quantum-optical detection.

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

Solution Approach 2:

The patent utilizes changes in the NV center's spin state parameters under different magnetic field conditions. By monitoring the photoluminescence intensity and spectral characteristics of the NV center, which change in response to magnetic field strength and direction, the system achieves sensitive magnetic field detection with simplified equipment.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If multiple sensors are used to determine spatial distribution, then spatial resolution improves, but equipment effort and resources increase

Engineering Contradiction:
Improvespatial resolutionVSAvoidnumber of sensors
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent merges multiple NV centers into a single diamond crystal substrate, creating an integrated sensor array. Multiple NV centers can be embedded within one diamond waveguide, allowing simultaneous measurement at multiple spatial locations while using a single unified detection system, thereby reducing the total quantity of separate sensor components needed.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs a composite structure combining diamond material with embedded NV centers. The diamond substrate serves as both the structural platform and the sensing medium, with NV centers distributed throughout providing multiple measurement points. This composite approach enables spatially resolved measurements within a single integrated component.

Inventive Principle:
Principle #40Composite materials

3Measurement precision

If high sensitivity magnetic field detection is achieved, then detection limit improves, but device complexity and cost increase

Engineering Contradiction:
Improvedetection limitVSAvoidcryotechnology requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent exploits changes in the NV center's optical and magnetic parameters to achieve high sensitivity detection. The NV center's photoluminescence properties change in response to magnetic fields, allowing detection limits of 10 fT to 1 pT through optical measurement techniques that do not require cryogenic temperatures, thus maintaining high sensitivity while simplifying the device.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces cryogenic cooling systems with room-temperature quantum sensing. The diamond NV center's quantum properties remain stable and functional at room temperature, eliminating the need for complex cryotechnology infrastructure while achieving comparable or superior detection sensitivity to conventional low-temperature systems.

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

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

The sensor achieves high sensitivity for detecting magnetic fields between 10 fT and 1 pT with atomic resolution, suitable for magnetoencephalography and other applications, and does not require complex cryotechnology, ensuring reliable and cost-effective operation.

Implementation Method 1

detect a magnetic field with the sensor according to the invention by subjecting the sensor, or at least the location of the NV center, to microwave radiation in order to excite electronic transitions between the singlet state and the doublet states

Methodology Applied
Scientific EffectMicrowave radiation excitation: Microwave Radiation

Implementation Method 2

The excitation can be detected optically by the signal propagating in the waveguide

Methodology Applied
Scientific EffectOptical detection: Photoluminescence

Implementation Method 3

Optical signals are totally reflected at the interfaces of the core and thus guided along the longitudinal extent of the waveguide

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 4

During operation of the sensor, light, which can originate, for example, from a semiconductor laser, a light-emitting diode, or a superluminescent diode, is coupled into the waveguide. The light exits the waveguide at its opposite end and is directed to a detector there

Methodology Applied
Scientific EffectOptical signal propagation: Optical Fibre

Implementation Method 5

Applying a magnetic field removes the degeneracy of the doublet, so that the spectroscopic analysis of the NV center can, in principle, be used as a magnetic field sensor

Methodology Applied
Scientific EffectZeeman effect: Zeeman Effect

Data Source

PatentEP3373023B1Sensor and method for its production and application
Publication Date: 2020.05.06 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3373023B1 patent drawingFigure 1~3
  • EP3373023B1 patent drawingFigure 4~6
  • EP3373023B1 patent drawingFigure 7~11

AI summary

The invention relates to a sensor (1) with a substrate (10) having a first side (11) and an opposing second side (12), wherein at least one waveguide (2) is arranged on the first side, the waveguide containing or consisting of diamond (20), and wherein at least one NV center (3) is arranged in the waveguide (2). The invention further relates to a method for measuring a magnetic field with such a sensor and a method for manufacturing such a sensor.