Dual-Chamber Atomic Magnetometer Cell for Low-Noise Gradiometry

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Solution Overview

Problem

Existing optically-pumped atomic magnetic gradiometers face challenges with practicality and noise due to single confining chambers and separate magnetometers, leading to impractical sample placement and increased noise from uncorrelated fluctuations in temperature and atomic density.

Innovation Solution

A cell design with two separated confining chambers, each receiving co-propagating pump and probe light beams, allowing for correlated noise cancellation and improved sensitivity through optical cavities with partial reflectivity walls, enabling sub-mm spatial resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a single confining chamber is used with two measuring zones, then the cell size can be reduced, but the atoms diffuse between zones causing the zones to become practically a single measuring zone

Engineering Contradiction:

Improvecell sizeVSAvoidmeasuring zone separation

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The single confining chamber is divided into two separate confining chambers (first confining chamber and second confining chamber), each containing its own alkali atoms. This segmentation prevents atom diffusion between measuring zones while maintaining a compact cell structure, as each chamber is independently sealed and contains a fixed population of atoms for precise gradiometric measurements.

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If probe beam enters from both front and back faces of the cell, then both measuring zones can be accessed, but sample placement close to the cell becomes impractical

Engineering Contradiction:

Improveoptical accessVSAvoidsample placement flexibility

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The optical access is segmented so that only the first confining chamber receives the probe beam through the front face, while the second confining chamber is accessed through the back face. This asymmetric arrangement allows magnetic samples to be placed close to the front face without interfering with the optical path, as the probe beam only needs to access one chamber through the front.

Inventive Principle:

Principle #1Segmentation

3Measurement precision

If separate magnetometers or cell arrays are used, then measuring zones can be physically separated, but uncorrelated noise from temperature and atomic density fluctuations increases

Engineering Contradiction:

Improvemeasuring zone separationVSAvoidnoise level

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

Two separate confining chambers are merged into a single integrated cell structure with shared physical boundaries and environmental conditions. This merging allows the chambers to experience correlated temperature and pressure fluctuations, which are then differentially rejected during gradiometric measurements, reducing uncorrelated noise while maintaining physical separation of the measuring zones.

Inventive Principle:

Principle #5Merging (Combining)

4Measurement precision

If optical cavities with partial reflectivity walls are used, then sensitivity is improved, but device complexity increases

Engineering Contradiction:

Improvemagnetic sensitivityVSAvoidoptical cavity structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Optical cavity properties are applied locally only to the walls facing the probe beam path, with specific walls having partial reflectivity to form the cavity resonator. This localized application of optical cavity technology enhances magnetic sensitivity along the measurement axis while keeping other parts of the cell structure simple and avoiding unnecessary complexity throughout the entire device.

Inventive Principle:

Principle #3Local quality

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 design achieves enhanced magnetic sensitivity and sub-mm spatial resolution by canceling common noise within the cell, surpassing the limitations of single-chamber designs and reducing noise from separate magnetometers.

Implementation Method 1

pump light polarized to spin polarize the alkali atoms

Methodology Applied

Scientific EffectOptical pumping: Photoelectric Effect

Implementation Method 2

optical cavities with partial reflectivity walls

Methodology Applied

Scientific EffectOptical cavity resonance: Reflection

Implementation Method 3

co-propagating pump and probe light beam, including pump light polarized to spin polarize the alkali atoms

Methodology Applied

Scientific EffectFaraday effect: Faraday Effect

Data Source

PatentUS12481008B2Cavity cell for an optically-pumped atomic magnetometer and a magnetic gradiometer, and a system comprising the gradiometer and a microscopy system

Publication Date: 2025.11.25 INSTITUCIO CATALANA DE RECERCA I ESTUDIS AVANCATS (ICREA)

AI summary

Provided is a cell for optically-pumped atomic magnetic gradiometry that includes a first confining chamber containing alkali atoms and configured to receive a co-propagating pump and probe light beam, including pump light polarized to spin polarize the alkali atoms, and at least a second confining chamber containing alkali atoms, distanced from the first confining chamber, and which is also configured to receive a co-propagating pump and probe light beam. Also provided are an optically-pumped atomic magnetic gradiometer including the presently disclosed and a system that includes the presently disclosed gradiometer and a microscopy system.