Split-Ring Resonator for Uniform NV Center Imaging
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Solution Overview
Problem
Current optically detected magnetic resonance imaging systems face limitations in precision and sensitivity due to non-uniform and inefficient microwave magnetic field coupling to Nitrogen-Vacancy (NV) centers in diamond, particularly over large areas, which restricts their application in bio-imaging and magnetometry.
Innovation Solution
A double split-ring microwave resonator integrated into a substrate, such as a printed circuit board, is used to provide a uniform and efficient microwave magnetic field coupling to NV centers, enabling precise and sensitive magnetic field imaging over large areas by tuning the resonator's frequency and quality factor to match the electron spin resonance frequency of the NV centers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional microwave field coupling methods are used, then the system structure is simple, but the magnetic field uniformity and coupling efficiency deteriorate over large areas
Solution Approach 1:
The resonator is divided into multiple split rings (e.g., two or more) arranged in a specific configuration. Each split ring segment contributes to the overall magnetic field generation, allowing the system to maintain field uniformity across larger areas by distributing the coupling function across multiple segmented structures rather than relying on a single conventional coupling method
Solution Approach 2:
The patent transitions from conventional one-dimensional or simple planar microwave coupling to a multi-dimensional resonator structure with split rings arranged in specific geometric configurations. This dimensional complexity in the resonator design enables uniform magnetic field distribution over expanded two-dimensional imaging areas, resolving the trade-off between field uniformity and imaging area
2Loss of energy
If conventional microwave coupling is used, then the device complexity is low, but the coupling efficiency and interaction strength with NV centers deteriorate
Solution Approach 1:
The system employs resonant oscillation at the electron spin resonance frequency of NV centers. The split-ring resonator is designed to resonate at this specific frequency, creating strong coupling between the microwave magnetic field and the NV center spins. This resonant enhancement dramatically improves coupling efficiency and interaction strength, overcoming the complexity of the resonator structure through frequency-selective energy transfer
Solution Approach 2:
The resonator parameters (geometry, size, material properties) are specifically tuned to match the electron spin resonance frequency of NV centers. By adjusting these parameters to achieve resonant conditions, the system maximizes the magnetic field strength and coupling efficiency at the target frequency, transforming the complex resonator structure into an efficient energy transfer mechanism
3Area of stationary object
If the resonator is designed for large area coverage, then the imaging area increases, but the magnetic field uniformity deteriorates
Solution Approach 1:
The resonator is divided into multiple split rings (e.g., two or more) arranged in a specific configuration. Each split ring segment contributes to the overall magnetic field generation, allowing the system to maintain field uniformity across larger areas by distributing the coupling function across multiple segmented structures rather than relying on a single conventional coupling method
Solution Approach 2:
The multi-split-ring resonator structure serves multiple functions simultaneously: it generates the microwave magnetic field, provides frequency selectivity through resonance, and maintains field uniformity across extended areas. This multi-functional design allows the same structure to achieve large area coverage while preserving magnetic field uniformity, unlike conventional single-function coupling methods
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 enables high-resolution, uniform magnetic field imaging over areas of several mm² with low variance, enhancing the sensitivity of magnetic sensing and bio-imaging applications, and allowing for large-volume NV center addressing with improved interaction strength and efficiency.
Implementation Method 1
an electromagnetic field resonator including two or more resonant structures... at least a first resonant structure configured to provide a magnetic field at a sample positioned in proximity to the first resonant structure, the sample being characterized by an electron spin resonance frequency
Implementation Method 2
provide a magnetic field at a sample positioned in proximity to the first resonant structure
Implementation Method 3
Optically detected magnetic resonance imaging with an electromagnetic field resonator... an optical coupler positioned in proximity to the first resonant structure, and configured to receive an output optical signal from the sample, the output optical signal being generated based at least in part on a magnetic field generated by the electromagnetic field resonator
Data Source
AI summary
Measuring a sample includes providing a magnetic field at the sample using an electromagnetic field resonator. The electromagnetic field resonator includes two or more resonant structures at least partially contained within dielectric material of a substrate, at least a first resonant structure configured to provide the magnetic field at the sample positioned in proximity to the first resonant structure. The sample is characterized by an electron spin resonance frequency. A size of an inner area of the first resonant structure and a number of resonant structures included in the electromagnetic field resonator at least partially determine a range of an operating resonance frequency of the electromagnetic field resonator that includes the electron spin resonance frequency. Measuring the sample also includes receiving an output optical signal from the sample generated based at least in part on a magnetic field generated by the electromagnetic field resonator.