Fabry-Pérot Fluid Refractometer for Bubble-Resistant Measurement
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Solution Overview
Problem
Existing refractometers are sensitive only to surface variations of the refractive index, require fluid flow for analyte interaction, and are prone to bubble interference, leading to non-instantaneous and complex calculations.
Innovation Solution
A sensor using a Fabry-Pérot cavity with planar entry and reflection exit guides, optically coupled through an acute angle, allows for instantaneous refractive index measurement without fluid flow and bubble interference, utilizing a power divider for simultaneous measurement across multiple sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If waveguide-based interferometric techniques are used, then sensitivity to surface refractive index variations is improved, but measurement time increases and bubble interference occurs
Solution Approach 1:
The patent changes the measurement parameter from surface-only detection to volume-integrated detection by using a Fabry-Pérot cavity resonance condition. The resonance wavelength depends on the average refractive index of the entire fluid volume in the cavity, enabling instantaneous measurement of bulk fluid properties without requiring analyte interaction time.
Solution Approach 2:
The patent replaces the mechanical/chemical interaction mechanism (analyte binding to biorecognition elements on waveguide surfaces) with an optical resonance mechanism. The Fabry-Pérot cavity uses standing wave resonance conditions that are sensitive to the average refractive index of the enclosed fluid volume, eliminating the need for fluid flow and interaction time.
2Measurement precision
If waveguide-based interferometric techniques are used, then surface refractive index detection is improved, but device complexity and signal processing complexity increase
Solution Approach 1:
The patent replaces complex computational signal processing with a direct optical measurement approach. The Fabry-Pérot resonance condition provides a direct relationship between the resonance wavelength and the average refractive index of the fluid, eliminating the need for complex calculations to refer variations to surface properties.
3Measurement precision
If waveguide-based interferometric techniques are used, then surface interaction capability is improved, but reliability decreases due to bubble sensitivity
Solution Approach 1:
The patent changes the detection parameter from surface-localized evanescent field interaction to volume-averaged refractive index measurement. The Fabry-Pérot cavity integrates the optical path through the entire fluid volume, making the measurement representative of bulk fluid properties and insensitive to localized disturbances such as bubbles on the waveguide surface.
4Measurement precision
If Mach-Zehnder interferometer with biorecognition elements is used, then analyte detection capability is improved, but measurement time increases due to required fluid flow
Solution Approach 1:
The patent replaces the mechanical fluid flow and chemical binding mechanism with an optical resonance mechanism. The Fabry-Pérot cavity measures the average refractive index of the fluid volume directly through resonance conditions, eliminating the need for fluid flow to transport analytes to surface-bound biorecognition elements.
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
Enables rapid, accurate, and bubble-resistant refractive index measurement of fluids, simplifying signal processing and reducing sensitivity to surface variations.
Implementation Method 1
a Fabry-Pérot cavity configured to accommodate a fluid
Implementation Method 2
a planar reflection exit guide optically coupled to the planar entry guide by the Fabry-Pérot cavity, including an optical axis at the first face forming an acute opening angle
Data Source
AI summary
The invention relates to a sensor, including:a planar entry guide comprising a first exit face and a planar transmission exit guide comprising a second entry face,a Fabry-Pérot cavity configured to accommodate a fluid, and delimited by the first exit face of the planar entry guide and by the second entry face of the planar transmission exit guide,a planar reflection exit guide optically coupled to the planar entry guide by the Fabry-Pérot cavity, including an optical axis at the first face forming an acute opening angle with an optical axis at the first face of the planar entry guide,the Fabry-Pérot being arranged so that a normal to the first face constitutes a bisector of the opening angle.