Gas Detection Device Using Segmented Cavity and Diffraction Grating
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Solution Overview
Problem
Existing gas and particle detection devices struggle to accurately detect low concentrations of gases or particles due to inadequate control over light-matter interaction, leading to signal losses and limited detection ranges, and are typically designed for a single type of gas or particle over a restricted concentration range.
Innovation Solution
A gas or particle detection device featuring a cavity with parallel reflecting walls and single-mode optical waveguides, where the diffraction grating pitch is optimized to minimize signal losses and allow precise control over light interaction length based on the type and concentration of the gas or particle, using a method that involves choosing the pitch to minimize a specific equation, thereby ensuring optimal light path within the interaction cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If single-mode hollow cavities are used to control interaction length, then measurement precision is improved, but device complexity increases and signal loss increases due to numerous reflections
Solution Approach 1:
The cavity is divided into multiple sections with different interaction lengths, allowing selective use of different path lengths for different concentration ranges. This segmentation enables precise control of light-matter interaction while reducing the number of reflections needed for each measurement range.
Solution Approach 2:
The system dynamically selects between different interaction paths (single-pass vs. multi-pass) depending on the concentration range being measured. For high concentrations, a shorter interaction path is used; for low concentrations, a longer interaction path is activated, optimizing the balance between precision and signal loss.
2Measurement precision
If single-mode hollow cavities are used to control interaction length, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The optical path is segmented into multiple discrete interaction regions within the cavity, each optimized for specific concentration ranges. This allows precise control of interaction length without requiring a completely complex cavity design, as each segment can be independently optimized.
Solution Approach 2:
The cavity structure is designed to serve multiple functions: it provides both single-pass and multi-pass optical paths, supports different interaction lengths, and can detect multiple concentration ranges using the same physical structure, thereby reducing overall device complexity.
3Loss of energy
If larger multimode hollow cavities are used to reduce signal loss, then loss of energy is reduced, but measurement precision deteriorates due to inability to control interaction length
Solution Approach 1:
The large multimode cavity is segmented into multiple functional zones, with specific regions dedicated to different interaction lengths. This allows the cavity to maintain its large size for reduced signal loss while introducing precise control mechanisms in specific segments.
Solution Approach 2:
Different regions of the cavity are assigned different optical properties and interaction characteristics. Specific local zones are optimized for precise interaction length control, while other regions provide the large volume needed to minimize signal loss, combining both requirements in a single structure.
4Measurement precision
If the device is designed for a single type of gas or particle over a restricted concentration range, then measurement precision is improved, but adaptability deteriorates
Solution Approach 1:
The detection device is designed with multiple interaction paths and configurable parameters that allow it to detect different types of gases and particles across wide concentration ranges. The same physical structure can be configured for high-precision detection in restricted ranges or extended-range detection by adjusting optical path selection and interaction length parameters.
Solution Approach 2:
The system dynamically adapts its detection parameters, interaction length, and optical path selection based on the type and concentration of the target analyte. This dynamic configuration allows the device to maintain high measurement precision across diverse applications and concentration ranges.
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 detection of gases or particles over a wide concentration range or multiple types over a restricted range with minimized signal losses, allowing for precise control of light interaction, thus improving detection accuracy and sensitivity.
Implementation Method 1
each optical waveguide having in its second end of width l2 a diffraction grating having a distinct pitch P chosen as a function of the wavelength λ of the light beam propagated in the optical waveguide associated with said diffraction grating
Implementation Method 2
an interaction cavity of gas or particles with the light beam having first and second reflective walls substantially parallel to each other and facing each other
Implementation Method 3
A light attenuation detector is based on the absorption or scattering property of the element to be detected: part of the light beam interacting with the element is absorbed or scattered
Implementation Method 4
A light attenuation detector is based on the absorption or scattering property of the element to be detected: part of the light beam interacting with the element is absorbed or scattered
Implementation Method 5
single-mode optical waveguides each having a first end of width l1 optically coupled to the light source and a second end of width l2, greater than the width l1, optically coupled to a first end of the interaction cavity
Data Source
Figure 1~2b
Figure 3a
Figure 3b
AI summary
An aspect of the invention concerns a device (10, 10') for detecting gas or particles comprising: - a light source capable of emitting a light beam, - an interaction cavity (12) comprising first and second reflective walls (123, 124) substantially parallel to one another, - a plurality of monomodal optical waveguides (13b), each having a first end (13b1) with width 11 optically coupled to the light source, and a second end (13b2) with width 12, greater than the width 11, optically coupled to a first end (121) of the interaction cavity, each optical waveguide comprising, in its second end with width 12, a diffraction grating (13b3) having an interval P particularly chosen according to a concentration C and a parameter a of interaction with the light beam of a type of gas or particles to detect; - and a detector (14) coupled to a second end (122) of the interaction cavity.