Oblique Radiation Source Structure for PAS Gas Sensor Sensitivity
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Solution Overview
Problem
Current gas sensors face challenges in achieving cost-effective production while maintaining reliability and accuracy, particularly in implementing improved radiation sources for photo-acoustic spectroscopy (PAS) sensors that require reduced fabrication complexity and adequate sensitivity for gas detection.
Innovation Solution
A radiation source with an emitter structure and a layer element featuring a radiation deflection structure that optically couples to a cavity, deflecting the radiation emission characteristic to enhance interaction with the target gas, allowing for oblique launching of narrowband electromagnetic radiation, thereby increasing absorption and detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional radiation source is used in gas sensors, then the fabrication process is simpler, but the detection sensitivity and absorption path length are insufficient
Solution Approach 1:
The patent introduces a layer element with a specific optical thickness (quarter-wave or half-wave thickness) to modify the radiation emission characteristic in the optical dimension. This dimensional approach to controlling radiation direction enables oblique launching without complex mechanical structures, resolving the contradiction between detection sensitivity and fabrication complexity
Solution Approach 2:
The patent changes the optical parameters of the radiation source by introducing a layer element with specific refractive index and thickness. This parameter modification transforms the radiation emission characteristic from normal to oblique direction, improving detection sensitivity while keeping the fabrication process relatively simple through standard thin-film deposition techniques
2Length of stationary object
If the radiation emission characteristic is deflected obliquely, then the absorption path length in the cavity is increased, but the emitter structure requires additional layer elements
Solution Approach 1:
The layer element acts as an intermediary component between the emitter structure and the cavity. It mediates the radiation emission characteristic by deflecting it obliquely, thereby increasing the absorption path length in the cavity without requiring direct modification of the emitter structure itself. This resolves the contradiction by introducing a simple intermediate layer rather than complicating the emitter
Solution Approach 2:
The layer element with specific optical thickness controls the radiation direction in the angular dimension, transforming normal emission into oblique emission. This dimensional control of radiation characteristics achieves longer absorption path length while maintaining a simple two-component structure (emitter + layer element)
3Reliability
If narrowband electromagnetic radiation is launched obliquely into the cavity, then the interaction efficiency with target gas is enhanced, but the radiation source requires precise optical coupling
Solution Approach 1:
The layer element with specific optical thickness (quarter-wave or half-wave) provides self-aligning optical coupling. The interference-based optical path control inherent in the layer element design automatically ensures proper phase and direction of the oblique radiation, reducing the need for external precision alignment mechanisms and manual adjustment during manufacturing
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 enhances the absorption path length and interaction efficiency within the gas sensor cavity, improving the detection sensitivity and reliability of gas sensors while reducing fabrication complexity and costs.
Implementation Method 1
a layer element coupled to the main radiation emission region of the emitter structure, wherein the layer element comprises a radiation deflection structure configured for deflecting the radiation emission characteristic of the emitter structure with respect to the surface normal of the main radiation emission region of the emitter structure
Implementation Method 2
the cavity is arranged for providing an optical interaction path for an interaction of the narrowband electromagnetic radiation having a center wavelength λ0 with a target gas in the cavity
Data Source
Figure 1a
Figure 1b
Figure 1c
AI summary
A radiation source (10) for obliquely launching a narrowband electromagnetic radiation (11) into a cavity (12), comprises an emitter structure (14) having a main radiation emission region (14-1) for emitting the narrowband electromagnetic radiation (11), wherein the emitter structure (14) is optically coupled to the cavity (12), and a layer element (18) coupled to the main radiation emission region (14-1) of the emitter structure (14), wherein the layer element (18) comprises a radiation deflection (distortion) structure (20) configured for deflecting the radiation emission characteristic of the emitter structure (14) with respect to the surface normal of the main radiation emission region (14-1) of the emitter structure (14).