Deformable Interferometric Sensor for Volatile Organic Compound Detection
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Solution Overview
Problem
Existing chemical sensors lack the dynamic range and remote interrogation capabilities required for field deployment and efficient detection of volatile organic compounds, particularly in applications like gas chromatography, where high limits of detection are necessary.
Innovation Solution
A deformable interferometric sensor using in-plane silicon Fabry-Perot interferometers functionalized with polymers that swell upon analyte absorption, causing mechanical deformation and resonance wavelength shifts proportional to analyte concentration, allowing for field deployment and remote interrogation without the need for local energy sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If polymer swelling is used to detect analyte concentration, then sensitivity to analyte absorption is improved, but device complexity increases due to integration of polymer functionalization with interferometer
Solution Approach 1:
The patent combines the polymer functionalization layer directly with the interferometer structure, merging the sensing element (polymer) and the detection element (interferometer) into a single integrated device. This eliminates the need for separate polymer coating steps and simplifies the overall device architecture while maintaining high sensitivity to analyte absorption.
Solution Approach 2:
The interferometer structure serves multiple functions: it acts as both the mechanical substrate and the optical detection element. The same structure that provides mechanical support also enables interferometric measurement of polymer swelling, reducing the need for additional specialized components and simplifying device complexity.
2Ease of manufacture
If in-plane Fabry-Perot interferometer configuration is used, then integration with microfluidic systems is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent transitions from traditional out-of-plane Fabry-Perot interferometer geometry to an in-plane configuration. This dimensional change allows the interferometer to be fabricated using standard planar microfabrication techniques compatible with microfluidic systems, significantly easing manufacturing integration while the precise alignment is achieved through lithographic patterning rather than mechanical assembly.
3Adaptability or versatility
If passive optical fiber alignment is used for remote interrogation, then field deployment capability is improved, but optical fiber positioning precision requirements increase
Solution Approach 1:
The patent incorporates alignment grooves and positioning features during the initial fabrication of the interferometer device. These pre-formed structural elements guide and constrain optical fiber placement, ensuring precise alignment is achieved automatically during assembly without requiring complex adjustment procedures in the field. This preliminary action enables passive alignment that maintains high precision while simplifying field deployment.
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 sensor achieves high sensitivity and dynamic range for detecting volatile organic compounds, enabling efficient field deployment and remote monitoring with integrated microfluidic systems and passive optical fiber alignment, maximizing sensitivity to polymer swelling.
Implementation Method 1
a polymer provided between the reflectors, the polymer exhibiting expansion along the optical axis of the optical fiber upon absorption of at least one analyte
Implementation Method 2
the polymer exhibiting expansion along the optical axis of the optical fiber upon absorption of at least one analyte
Implementation Method 3
a pair of parallel and spaced apart reflectors forming a Fabry-Perot cavity
Implementation Method 4
the pair of reflectors separated by a distance L; an optical fiber interfaced with the outer surface of each one of the reflectors
Data Source
AI summary
There is described a deformable interferometric sensor in which polymer swelling, upon analyte absorption, is used to deform an on-chip silicon Fabry-Perot interferometer (FPI). The magnitude of the deformation, recorded through the resonance wavelength shift, is proportional to the analyte concentration.