Optical Resonator Magnetometer with Internal Magnetostrictive Void
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Solution Overview
Problem
Current optical magnetometers face limitations in sensitivity and bandwidth, making them less effective for applications like microfluidic magnetic resonance imaging, neural imaging, and spin physics studies, particularly due to challenges with integration and handling of magnetostrictive materials in chip-based architectures and limited sensitivity to magnetic resonance signals.
Innovation Solution
An optical magnetometer design featuring a central void optical resonator with a magnetostrictive material inside, where changes in the magnetostrictive material's dimensions cause changes in mechanical modes of the resonator, enhancing sensitivity and bandwidth through improved mechanical coupling and fabrication methods such as chemical etching, focused ion beam milling, and epoxy bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetostrictive material is coated on the surface of a solid optical resonator, then the device structure is simple, but the sensitivity and bandwidth are limited
Solution Approach 1:
The patent extracts the magnetostrictive material from the surface coating configuration and places it inside a central void of the optical resonator. This extraction allows the magnetostrictive material to be directly coupled to the mechanical modes of the resonator, significantly improving sensitivity and bandwidth while maintaining a relatively simple overall device structure.
Solution Approach 2:
The patent transitions from a two-dimensional surface coating configuration to a three-dimensional internal placement configuration. By positioning the magnetostrictive material within the central void of the resonator, the design enables stronger mechanical coupling and improved interaction with the optical modes, thereby enhancing sensitivity without proportionally increasing device complexity.
2Measurement precision
If diamond substrate with NV centres is used, then sensitivity down to 100 pT is achieved, but integration in chip-based architecture is challenging
Solution Approach 1:
The patent segments the magnetometer into distinct functional components: the optical resonator structure and the magnetostrictive material. This segmentation allows each component to be optimized and fabricated separately using standard techniques, then integrated together, making chip-based architecture feasible while maintaining high sensitivity performance.
Solution Approach 2:
The optical resonator design serves multiple functions: it provides the optical cavity for detection, contains the magnetostrictive material, and enables mechanical mode coupling. This multi-functionality reduces the need for separate components, simplifying integration into chip-based architectures while achieving sensitivity comparable to NV centre-based devices.
3Measurement precision
If magnetostrictive material is placed inside central void of optical resonator, then sensitivity and bandwidth are improved, but fabrication complexity increases
Solution Approach 1:
The patent employs preliminary actions in the fabrication process by first creating the central void in the optical resonator, then subsequently placing the magnetostrictive material into this pre-prepared space. This sequence of operations simplifies the overall fabrication process and allows for better control of manufacturing precision compared to attempting to integrate the materials simultaneously.
Solution Approach 2:
The central void acts as an intermediary structure that facilitates the integration of the magnetostrictive material with the optical resonator. This intermediary design allows for easier manipulation and precise positioning of the magnetostrictive material during fabrication, reducing the complexity and improving the precision of the manufacturing process.
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 significantly improved sensitivity and bandwidth, enabling applications such as microfluidic MRI, neural imaging, and spin physics studies with reduced need for cryogenic cooling and vacuum, suitable for remote detection and low-power operation.
Implementation Method 1
a magnetostrictive material was attached to the microcavity so that a change in the dimensions of the magnetostrictive material under the influence of a magnetic field was translated to stress in the microcavity causing a change in the mechanical modes of the microcavity
Implementation Method 2
an optical resonator having optical modes and mechanical modes
Data Source
AI summary
An optical magnetometer comprising: an optical resonator having a central void; and a magnetostrictive material located in the central void such that a change in dimension of the magnetostrictive material causes a change in mechanical modes of the optical resonator. Also a method of making the optical magnetometer.