Gas Absorption Spectrometer Resonance Locking via Laser Modulation
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Solution Overview
Problem
Existing gas absorption spectrometers face challenges in precisely controlling the resonator into a resonant state due to insufficient responsiveness of piezoelectric elements, leading to instability in laser light frequency.
Innovation Solution
A gas absorption spectrometer system utilizing a modulator and piezoelectric element, controlled by a controller, to stabilize laser light frequency through feedback mechanisms, ensuring precise resonant state maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If piezoelectric element is used to control cavity length of resonator, then resonator can be adjusted to resonant state, but responsiveness is insufficient and control precision deteriorates at certain light frequencies
Solution Approach 1:
The patent introduces a modulator as an intermediary device between the light source and resonator. The modulator adjusts the frequency of laser light before it enters the resonator, serving as a mediator to compensate for the insufficient responsiveness of the piezoelectric element. This allows precise frequency control without relying solely on the slow mechanical adjustment of the piezoelectric element.
Solution Approach 2:
The patent changes the approach from directly controlling the resonator's physical parameter (cavity length via piezoelectric element) to controlling the light's parameter (frequency via modulator). By adjusting the light frequency parameter instead of the cavity length parameter, the system achieves faster and more precise control of the resonant state.
2Stability of the object's composition
If piezoelectric element controls cavity length based on reflected light feedback, then frequency stabilization is attempted, but responsiveness is insufficient leading to inability to maintain resonant state
Solution Approach 1:
The modulator acts as an intermediary that responds quickly to feedback signals from the photodetector. Instead of relying on the slow piezoelectric element to adjust cavity length, the modulator rapidly adjusts the laser frequency based on the error signal, thereby achieving both stability and fast responsiveness.
Solution Approach 2:
The patent replaces the mechanical adjustment system (piezoelectric element physically changing cavity length) with an optical/electronic control system (modulator changing light frequency). This substitution eliminates the mechanical response time limitation and achieves faster frequency stabilization.
3Device complexity
If only piezoelectric element is used for frequency control, then device structure remains simple, but measurement accuracy deteriorates due to inability to properly maintain resonant state
Solution Approach 1:
The modulator is introduced as an additional intermediary component that works in conjunction with the piezoelectric element. This modest addition to the device structure enables precise frequency control and proper maintenance of the resonant state, thereby significantly improving measurement accuracy without creating a complex system.
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 system effectively locks the laser light frequency, maintaining a stable resonant state and enhancing the accuracy of gas component concentration measurements.
Implementation Method 1
a piezoelectric element for changing a cavity length of the resonator
Implementation Method 2
a modulator disposed in an optical path between the light source and the resonator for modulating a frequency of the laser light
Implementation Method 3
a first photodetector for detecting light leaking from the resonator, a second photodetector for detecting light reflected by the resonator
Implementation Method 4
In the resonator, light is accumulated in a resonant state using the input laser light
Implementation Method 5
Cavity Ring-Down Spectroscopy (CRDS) is known as a type of gas absorption spectroscopy
Data Source
AI summary
A gas absorption spectrometer comprises a resonator for storing the sample, a light source for outputting laser light to the resonator, a modulator disposed in an optical path between the light source and the resonator for modulating a frequency of the laser light, a first photodetector for detecting light leaking from the resonator, a second photodetector for detecting light reflected by the resonator and returned to the light source side, a piezoelectric element for changing a cavity length of the resonator, and a controller. The controller, based on the light detected by the second photodetector, controls at least one of the modulator and the piezoelectric element to bring light in the resonator into a resonant state, and after changing the light in the resonator from the resonant state to a non-resonant state, measures a target component in the sample based on the light detected by the first photodetector.