Spin Defect Sensor Coupling Element
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Solution Overview
Problem
Existing spin defect sensor devices face challenges in fluorescence extraction due to the high refractive index of diamond and mismatch with free space or waveguides, leading to poor coherence and coupling efficiency of nanocrystals, and difficulties in scaling and fabricating diamond nanopillars.
Innovation Solution
The proposed sensor device comprises a tip portion with a coupling element and a diamond element bonded together, where the diamond element contains at least one spin defect. The coupling element, made of a material different from diamond, is formed integrally with a dielectric light-transmissive element to enhance optical coupling and reduce background fluorescence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diamond is used directly to couple optical signal from spin defect into free space or waveguide, then fluorescence extraction is achieved, but coupling efficiency is poor due to high refractive index mismatch
Solution Approach 1:
The patent introduces a coupling element made of a material with intermediate refractive index between diamond and free space/waveguide. This intermediary material serves as a refractive index bridge, enabling gradual transition of light from high-index diamond to low-index free space or waveguide, thereby significantly improving optical coupling efficiency and reducing reflection losses at the interface.
2Reliability
If nanocrystals are integrated in waveguides, then fluorescence extraction is enabled, but coherence is poor and orientation control is lost
Solution Approach 1:
The patent segments the diamond structure into a diamond element containing the spin defect and a separate coupling element. This segmentation allows the spin defect to remain in the high-coherence diamond environment while the coupling element handles the optical interface functions, thereby preserving coherence while enabling efficient fluorescence extraction.
3Reliability
If diamond nanopillars are used for collimating NV emissions, then fluorescence extraction is improved, but fabrication is challenging and scaling is difficult
Solution Approach 1:
The patent divides the system into a diamond element and a separate coupling element, allowing each to be optimized and fabricated independently. The coupling element can be manufactured using standard semiconductor fabrication techniques, avoiding the challenging diamond nanopillar fabrication process while maintaining effective fluorescence extraction.
Solution Approach 2:
The coupling element serves as an optical copy or interface structure that replicates the light-collimating function without requiring the complex diamond nanopillar structure. This copying approach enables the same optical functionality to be achieved with easier-to-manufacture materials and processes.
4Reliability
If diamond is used for coupling, then spin defect sensing is enabled, but background fluorescence of diamond decreases signal quality
Solution Approach 1:
The patent extracts the optical coupling function from the diamond material itself and places it in a separate coupling element. This extraction removes the source of background fluorescence (the diamond) from the optical path where it would interfere with the signal, while the diamond element retains its essential function of housing the spin defect.
5Reliability
If diamond is used extensively in the device, then spin defect functionality is maintained, but device cost increases and fabrication complexity increases
Solution Approach 1:
The patent segments the device into a diamond element (containing the spin defect) and a coupling element (made of easier-to-process material). This segmentation reduces the total amount of diamond required, lowering cost and simplifying fabrication while preserving the essential spin defect functionality in the diamond portion.
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 improves the optical coupling efficiency, reduces the amount of diamond material required, and simplifies fabrication, leading to enhanced fluorescence extraction and signal quality in spin defect sensors.
Implementation Method 1
The diamond element comprises at least one spin defect configured to emit an optical signal
Implementation Method 2
A key issue for spin defect sensors is fluorescence extraction, which generally is challenging due to the high refractive index of diamond and the high refractive index mismatch between diamond and free space and/or diamond and a corresponding waveguide
Data Source
Figure 1
Figure 2a~5
Figure 6a~8
AI summary
The present disclosure relates to a sensor device comprising a tip portion that comprises a coupling element and a diamond element bonded to the coupling element. The sensor device further comprises a dielectric light-transmissive element and a receiver element. The diamond element comprises at least one spin defect configured to emit an optical signal. The coupling element configured to couple the optical signal into the dielectric light-transmissive element is formed of a material different from diamond and is formed integrally with the dielectric light-transmissive element. The dielectric light-transmissive element is configured to couple the optical signal into the receiver element. The coupling element protrudes from the dielectric light-transmissive element.