Multi-Wavelength Laser Source for Gas Detection
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Solution Overview
Problem
The detection of hazardous gases in industrial and environmental settings is challenging due to their odorless and colorless nature, and intensity fluctuations caused by air turbulence, making it difficult to accurately locate and identify leaks using existing laser-based detection methods.
Innovation Solution
A compact, portable laser source that generates a set of sequential output beams with different center wavelengths in the mid-infrared range, utilizing a gain medium and a feedback assembly with a device mover to adjust the angle of incidence, enabling precise wavelength control and stability, which is combined with a sensor system for imaging and gas detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a laser source generates sequential output beams spanning the MIR range to detect multiple gases, then the detection capability is improved, but the device complexity increases
Solution Approach 1:
The patent employs a dynamic feedback device (diffraction grating) that can be rapidly positioned to different angles using a voice coil motor, enabling the laser to sequentially generate multiple wavelengths. This dynamic adjustment mechanism allows a single laser source to cover the entire MIR range, providing multi-gas detection capability without requiring multiple fixed-wavelength lasers, thus improving versatility while managing device complexity.
2Ease of operation
If the laser source is made compact and portable for field deployment, then the ease of operation is improved, but the manufacturing precision becomes more difficult to maintain
Solution Approach 1:
The patent incorporates a feedback mechanism using a position detector (encoder) that continuously monitors the angular position of the diffraction grating. This position feedback is fed to a control system that adjusts the voice coil motor to maintain precise wavelength selection. This closed-loop feedback system ensures wavelength accuracy is maintained even in the compact, portable design where mechanical tolerances are tighter, resolving the contradiction between portability and manufacturing precision.
3Measurement precision
If the laser rapidly sweeps through wavelengths to freeze atmospheric turbulence, then the measurement precision is improved, but the loss of time occurs during wavelength transitions
Solution Approach 1:
The patent implements a periodic wavelength sweeping mechanism where the feedback device rapidly oscillates through the MIR range in a continuous cycle. The system is synchronized to perform measurements at specific phases of this periodic sweep, ensuring that each wavelength measurement is captured during stable conditions. This periodic action allows the system to freeze atmospheric turbulence effects while maintaining continuous operation, minimizing time loss through efficient use of the sweeping cycle.
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 solution allows for accurate and rapid detection of hazardous gases by generating wavelength-specific beams that span a predetermined range, overcoming turbulence-induced intensity fluctuations and providing clear imaging of gas leaks, resulting in a lightweight, rugged, and self-contained detection system.
Implementation Method 1
The gain medium includes a first facet, and the gain medium is adapted to generate a beam that exits the first facet
Implementation Method 2
The feedback device is positioned in the path of the beam that exits the first facet and the feedback device redirects at least a portion of the beam back to the gain medium
Implementation Method 3
The device mover continuously adjusts an angle of incidence of the beam on the feedback device
Implementation Method 4
The position detector generates a position signal that relates to the angle of incidence of the beam on the feedback device
Implementation Method 5
The control system directs a pulse of power to the gain medium upon receipt of the first position signal and directs another pulse of power to the gain medium upon receipt of the second position signal
Data Source
Figure 1A~1B
Figure 2~3C
Figure 4A~6B
AI summary
A laser source (10) for emitting a set of sequential, different wavelength output beams (12) includes a gain medium (16), a feedback assembly (26) and a control system (30). The gain medium (16) includes a first facet (16A), and the gain medium (16) generates a beam (12A) that exits the first facet (16A). The feedback assembly (26) includes a feedback device (40) and a device mover (42). The feedback device (40) is positioned in the path of the beam (12A) that exits the first facet (16A) and the feedback device (40) redirects at least a portion of the beam (12A) back to the gain medium (16). The device mover (42) continuously adjusts an angle of incidence (θ) of the beam (12A) on the feedback device (40). The control system (30) selectively directs pulses of power to the gain medium (16) as the device mover (42) is continuously adjusting the angle of incidence (θ) of the beam (12A). Further, the laser source (10) can include a position detector (28) that generates a position signal that relates to the angle of incidence (θ) of the beam (12A) on the feedback device (40). In this embodiment, the control system (30) can selectively direct pulses of power to the gain medium (16) based on the position signal from the position detector (28). Further, the control system (30) can determine a center wavelength of the output beam (12) based on the position signal.