CRDS Laser Wavelength Locking via ICOS Narrow-Band Absorbers
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Solution Overview
Problem
Cavity Ringdown Spectroscopy (CRDS) instruments require expensive and complicated wavelength monitors to maintain accurate laser ringdown events, which is costly and prone to failure, especially in applications like next-generation gas-insulated switchgear where low-cost, moderate sensitivity is needed for measuring broad band absorber species.
Innovation Solution
The method uses nearby narrow-band absorbers to lock the laser wavelength through Integrated Cavity Output Spectroscopy (ICOS), employing a PID loop or alternative feedback schemes to maintain consistent ringdown wavelength, eliminating the need for external wavelength monitors and minimizing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If expensive wavelength monitors are used to maintain accurate laser ringdown events, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent introduces an intermediary substance (broad band absorber) that mediates between the laser and the wavelength monitoring function. The broad band absorber's absorption features serve as reference markers that the laser wavelength can be locked to, eliminating the need for complex external wavelength monitors while maintaining wavelength accuracy for detecting narrow band absorbers
Solution Approach 2:
The broad band absorber serves multiple functions simultaneously: it acts as a wavelength reference for locking the laser, provides absorption features for concentration measurement, and enables the system to function without external wavelength monitoring equipment. This multi-functionality reduces device complexity while maintaining measurement precision
2Measurement precision
If wavelength monitors are installed to ensure accurate wavelength, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive, complex wavelength monitoring equipment with a simple chemical reference (broad band absorber) that provides wavelength locking functionality at minimal cost. The broad band absorber acts as a low-cost, readily available reference standard that eliminates the need for expensive electronic wavelength monitors
Solution Approach 2:
The broad band absorber serves as a cost-effective intermediary that provides wavelength reference information without requiring expensive electronic monitoring equipment. This intermediary approach significantly reduces manufacturing costs while maintaining the ability to lock laser wavelength accurately
3Measurement precision
If single mode ringdown is used to maximize sensitivity, then measurement precision is improved, but adaptability to broad band absorber species decreases
Solution Approach 1:
The patent merges the advantages of single mode ringdown (high sensitivity for narrow band absorbers) with the capabilities needed for broad band absorber measurement. By combining single mode ringdown for detecting narrow band absorbers with ICOS for detecting broad band absorbers, the system achieves both high sensitivity and broad adaptability to different gas species
Solution Approach 2:
The system achieves multi-functionality by using single mode ringdown for narrow band absorber detection while simultaneously enabling broad band absorber detection through ICOS. This allows the same system to handle both high-sensitivity applications and broad-band applications, increasing overall adaptability
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 approach allows for accurate quantification of broad band absorbers without incurring manufacturing costs associated with expensive wavelength monitors, enhancing the robustness and serviceability of CRDS systems while maintaining measurement precision.
Implementation Method 1
Cavity Ringdown Spectroscopy (CRDS) is a powerful tool for the detection and quantification of small optical absorbers
Implementation Method 2
The absorbance of the light beam in the cavity is measured after the light beam has interacted with the mixture
Implementation Method 3
employing a PID loop or alternative feedback schemes to maintain consistent ringdown wavelength
Data Source
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AI summary
Systems and methods for measuring a value of constituents in a mixed constituent gas having at least one broad band absorber constituent therein and at least one lock constituent are provided. The system uses a combination of integrated cavity output spectroscopy and cavity ringdown spectroscopy to determine the measurement values of constituents in a cavity of a spectrometer. Cavity ringdown in the presence of the at least one broad band absorber constituent and a reference concentration value are used to determine the constituent measurement values when the spectral width of the laser tuning range is overlapped by the absorption band of the broad band absorber in the cavity.