ODMR Magnetic Field Sensing With Common-Mode Light Noise Rejection
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Solution Overview
Problem
Existing magnetic field measurement devices using optically detected magnetic resonance (ODMR) suffer from reduced measurement accuracy due to noise components caused by irradiation light, particularly laser light.
Innovation Solution
A measurement device and method that incorporates a magnetic resonance member, high frequency magnetic field generator, light emitting and receiving devices, and arithmetic processing units to perform common mode rejection and digital filter processing to suppress noise components and improve measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If excitation light is irradiated to the magnetic resonance member, then fluorescence is generated for detection, but noise components are introduced that reduce measurement accuracy
Solution Approach 1:
The patent segments the detection system into two separate detection paths: one for fluorescence signal detection and another for excitation light noise detection. By using separate photodetectors and signal processing channels, the system can independently characterize and subsequently remove noise components from the fluorescence measurement, thereby improving measurement accuracy despite the presence of excitation light.
Solution Approach 2:
The system implements feedback by continuously monitoring the excitation light intensity separately and using this information to dynamically adjust or subtract noise components from the fluorescence detection signal. This feedback mechanism allows real-time compensation for noise introduced by the excitation light, maintaining measurement accuracy.
2Measurement precision
If common mode rejection is applied to suppress noise, then measurement accuracy improves, but system complexity increases due to additional signal processing
Solution Approach 1:
The patent introduces an intermediary reference signal that captures the noise characteristics of the excitation light. This reference signal acts as a mediator between the noise source and the fluorescence detection signal, allowing the system to mathematically separate and remove noise components through correlation analysis without requiring complex hardware modifications.
Solution Approach 2:
The system creates a copy of the noise signal through separate detection of the excitation light path. By measuring the excitation light intensity independently and creating a corresponding noise model, the system can subtract this copied noise signature from the fluorescence signal, achieving noise suppression through straightforward signal arithmetic rather than complex processing.
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 solution effectively reduces noise interference, enhancing the accuracy of magnetic field measurements by utilizing common mode rejection and digital filtering techniques.
Implementation Method 1
electron spin resonance of a sensing member such as a diamond structure having nitrogen and lattice defects (NV center: Nitrogen Vacancy Center) is utilized
Implementation Method 2
The light emitting device emits excitation light irradiate to the magnetic resonance member
Implementation Method 3
The fluorescence light receiving device receives fluorescence emitted by the magnetic resonance member in response to the excitation light
Data Source
AI summary
A light receiving device receives fluorescence emitted by a magnetic resonance member in response to excitation light and generates a fluorescence sensor signal corresponding to a fluorescence intensity. A CMR arithmetic part performs common mode rejection with respect to the fluorescence sensor signal based on a reference light sensor signal of reference light that is obtained by branching the excitation light in consideration of nonlinearity of a level of the fluorescence sensor signal corresponding to an amount of the excitation light and generates a CMR signal. An A/D converter digitizes the CMR signal. An analog/digital converter digitizes the reference light sensor signal. An arithmetic processing device derives a measurement value of a measured field based on the digitized CMR signal and the digitized reference light sensor signal.