Optically Pumped Magnetometer with Shared Pump Light
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Solution Overview
Problem
Magnetoencephalography using optically pumped magnetometers faces challenges in miniaturization due to the need for multiple optically pumped magnetometers with complex pump light branching and noise interference.
Innovation Solution
The design includes a configuration where pump light is incident on one cell region and probe light on an orthogonal region, allowing for consecutive use of the same pump light across multiple cell regions, simplifying the pump light system and reducing noise interference by calculating differences in magnetic field intensities between regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple pump lasers are used to illuminate multiple cell regions, then each cell region can be independently excited, but the device complexity increases and miniaturization becomes difficult
Solution Approach 1:
The patent merges the pump light paths by using a single pump laser that sequentially illuminates multiple cell regions (first cell region and second cell region) through time-division multiplexing. The pump light is switched between different cell regions rather than using separate pump lasers for each region, thereby reducing device complexity while maintaining excitation reliability.
Solution Approach 2:
The system dynamically switches the pump light between different cell regions using optical switches or modulators. This dynamic allocation allows a single pump laser to serve multiple cell regions at different time intervals, eliminating the need for multiple static pump lasers and reducing overall system complexity.
2Reliability
If multiple independent pump light paths are prepared for multiple cell regions, then each region receives dedicated pump light, but the device size increases and miniaturization is hindered
Solution Approach 1:
The pump light is delivered to different cell regions in periodic intervals through time-division multiplexing. A single pump laser alternates between illuminating the first cell region and the second cell region, ensuring each region receives adequate pump light excitation while using a shared optical path that reduces the overall device volume.
Solution Approach 2:
The single pump laser performs multiple functions by serving different cell regions at different time intervals. This multi-functional approach allows one pump laser to replace what would traditionally require multiple dedicated pump lasers, thereby reducing the magnetometer volume while maintaining reliable pump light delivery to all cell regions.
3Measurement precision
If separate detection systems are used for each cell region, then measurement accuracy for each region is optimized, but the device complexity increases
Solution Approach 1:
The detection system merges multiple detection channels into a single integrated detection unit. Probe lights from different cell regions are combined and processed by a common detection system that can distinguish signals from different regions through time-division multiplexing or spatial encoding, thereby maintaining measurement precision while reducing detection system complexity.
4Productivity
If pump light branches are created for each cell region, then simultaneous illumination of all regions is achieved, but the device complexity and size increase
Solution Approach 1:
Instead of simultaneous parallel illumination, the system uses periodic sequential illumination where the pump light alternates between different cell regions in time-division multiplexed intervals. This periodic action maintains productivity by ensuring all regions are adequately excited while avoiding the complexity of creating and managing multiple simultaneous pump light branches.
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 enables miniaturization of optically pumped magnetometers while improving measurement accuracy by reducing common-mode noise and eliminating the need for multiple pump lasers, leading to a more compact and sensitive device.
Implementation Method 1
An optically pumped magnetometer measures a microscopic magnetic field by exciting alkali metal atoms through optical pumping and using spin polarization of the atoms
Implementation Method 2
using spin polarization of the atoms
Implementation Method 3
a probe laser configured to emit probe light including first probe light and second probe light for detecting change in a polarization angle caused by a magnetic field in an excited state of the alkali metal atoms
Data Source
AI summary
An optically pumped magnetometer includes cells configured to form a first cell region and a second cell region on a measurement target, a pump laser, a probe laser, a first optical system configured to cause pump light to be incident on the first cell region, a second optical system configured to cause the pump light having passed through the first cell region to be incident on the second cell region, a third optical system configured to cause first probe light to be incident on the first cell region, a fourth optical system configured to cause second probe light to be incident on the second cell region, detection portions configured to detect the first probe light having passed through the first cell region and the second probe light having passed through the second cell region, and a deriving portion configured to derive an intensity of a magnetic field.