Optical Cavity Gas Sensor for Low-Concentration Detection
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Solution Overview
Problem
Existing optical gas sensors face challenges in detecting low concentrations of target gases due to limited optical path lengths between the light source and detector, making it difficult to achieve low detection limits without increasing the physical distance between these components.
Innovation Solution
The use of a cavity enhanced gas sensor design with reflectors forming an optical cavity within a sample chamber, where light is reflected back and forth between two reflectors, effectively increasing the optical path length and enhancing the interaction with target gas molecules, thereby improving detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the physical distance between the light source and detector is increased to enhance detection sensitivity, then the detection limit improves, but the device complexity and size increase
Solution Approach 1:
The patent transforms the one-dimensional linear path between light source and detector into a multi-pass optical path using reflectors. The light travels back and forth between the sample chamber and reflectors multiple times, effectively increasing the optical path length from a simple linear distance to a folded path that achieves meters of equivalent path length in a compact device footprint.
Solution Approach 2:
The optical cavity formed by the reflectors and sample chamber creates a nested structure where light is trapped and reflected multiple times within the confined space. The sample chamber is positioned between the light source/detector assembly and the reflectors, creating a compact nested arrangement that maximizes the optical path within minimal physical volume.
2Measurement precision
If the physical distance between the light source and detector is increased to enhance detection sensitivity, then the detection limit improves, but the device size increases
Solution Approach 1:
The patent uses optical reflection to fold the light path into additional dimensions, allowing the light to traverse a long effective path length while the physical device maintains a compact form factor. The reflectors create a resonant cavity that multiplies the optical path without proportionally increasing the device volume.
3Device complexity
If a simple linear optical path is used between light source and detector, then the device complexity is reduced, but the detection sensitivity decreases
Solution Approach 1:
The patent introduces reflectors as intermediary components between the light source and detector. These reflectors mediate the light path by reflecting light back and forth through the sample chamber multiple times, enhancing the interaction between light and target gas molecules without requiring a complex optical system with multiple lenses and mirrors.
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 design allows for the detection of relatively low concentrations of target gases by increasing the effective optical path length, enabling more accurate and sensitive gas concentration measurements.
Implementation Method 1
At least a portion of the received light has reflected through the sample chamber between the first and the second reflector one or more times
Implementation Method 2
Spectroscopy offers a useful approach for sensing the concentration of a chosen target gas
Data Source
AI summary
Apparatuses, systems, and methods for a cavity enhanced absorption gas sensor. The gas sensor includes a sample chamber with a first reflector at a first end of the sample chamber and a second reflector at a second end of the sample chamber. The first and the second reflector form an optical cavity within the sample chamber. The sensor includes an illumination source which passes light through the first reflector and into the sample chamber and a detector which receives light from the sample chamber through the second reflector. This may increase an effective optical path length of the sensor and lower the limit of detection of the sensor.