Solid-State Spin Sensor Magic Angle Spinning Sensitivity

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Solution Overview

Problem

Current solid-state spin sensors face limitations in sensitivity due to short dephasing times, primarily caused by dipolar coupling between color center defects and paramagnetic impurities, which restricts their ability to accurately measure magnetic fields with high resolution and sensitivity.

Innovation Solution

The implementation of a magic-angle-spinning magnetic field, generated by combining a stationary uniform magnetic field with a rotating magnetic field, effectively cancels dipolar interactions, thereby increasing the dephasing and coherence times of the color center defects, leading to enhanced sensitivity and measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a fixed bias magnetic field is applied to the solid-state spin sensor, then the quantum energy levels can be distinguished and individually interrogated, but the dephasing time remains short due to dipolar coupling between color center defects

Engineering Contradiction:

Improvemagnetic field sensing precisionVSAvoiddephasing time

Core Design Contradiction:

Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The patent transforms the static bias magnetic field into a dynamic rotating magnetic field that rotates at the magic angle (54.7 degrees) relative to the quantization axis. This dynamic field configuration actively modulates the dipolar interactions between color center defects, causing them to average out over time and thereby extending the dephasing time while maintaining level distinction

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the orientation parameter of the magnetic field from a fixed alignment with the quantization axis to a rotating configuration at the magic angle. This parameter change (orientation angle) fundamentally alters the interaction dynamics, suppressing dipolar coupling effects and extending coherence time without sacrificing the ability to distinguish quantum energy levels

Inventive Principle:

Principle #35Parameter changes

2Reliability

If color center defects are used for sensing, then high-performance low-cost sensing is achieved, but dipolar coupling between defects limits sensitivity and resolution

Engineering Contradiction:

Improvesensing performanceVSAvoiddipolar coupling interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful dipolar coupling effect into a beneficial averaging process by rotating the magnetic field at the magic angle. The dipolar interactions that previously caused dephasing and sensitivity loss now average to zero over the rotation cycle, transforming the harmful coupling into a mechanism that extends dephasing time and improves sensitivity

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent applies periodic rotation of the magnetic field at the magic angle, creating a time-averaged suppression of dipolar interactions. This periodic modulation causes the harmful dipolar coupling to oscillate and average out over each rotation cycle, effectively eliminating its harmful impact on sensing performance

Inventive Principle:

Principle #19Periodic action

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 approach significantly extends the dephasing time from microseconds to milliseconds, improving the sensitivity of solid-state spin sensors by a factor of at least 70 and enabling more precise magnetic field measurements, suitable for applications like magnetoencephalography and space weather monitoring.

Implementation Method 1

The magnetic field source generates a magic-angle-spinning magnetic field that cancels dipolar interactions, thereby extending a dephasing time and/or a coherence time of the color center defects

Methodology Applied

Scientific EffectMagic angle spinning:

Implementation Method 2

The color center defects emit fluorescent light in response to the optical excitation radiation and the microwave radiation. The value of the physical quantity to be measured can be inferred from the quantity of the detected optical fluorescent light

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Implementation Method 3

The bias magnetic field shifts the different quantum energy levels so that each quantum energy level can be distinguished from the other quantum energy levels, allowing each quantum energy level to be individually interrogated

Methodology Applied

Scientific EffectZeeman effect: Zeeman Effect

Data Source

PatentUS10705163B2Stationary magic angle spinning enhanced solid state spin sensor

Publication Date: 2020.07.07 MASSACHUSETTS INST OF TECH

AI summary

Here we present a solid-state spin sensor with enhanced sensitivity. The enhanced sensitivity is achieved by increasing the T2* dephasing time of the color center defects within the solid-state spin sensor. The T2* dephasing time extension is achieved by mitigating dipolar coupling between paramagnetic defects within the solid-state spin sensor. The mitigation of the dipolar coupling is achieved by applying a magic-angle-spinning magnetic field to the color center defects. This field is generated by driving a magnetic field generator (e.g., Helmholtz coils) with phase-shifted sinusoidal waveforms from current source impedance-matched to the magnetic field generator. The waveforms may oscillate (and the field may rotate) at a frequency based on the precession period of the color center defects to reduce color center defect dephasing and further enhance measurement sensitivity.