Trigger Unit for Fast Infrared Spectra Calibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing infrared spectroscopic systems using tunable quantum cascade lasers face challenges in achieving efficient calibration of measurement data due to the compromise between beam quality and wavelength accuracy, especially at high tuning rates, limiting their applications in remote detection and spectroscopy.
Innovation Solution
An optical device with a trigger unit that utilizes two trigger signals synchronized with the laser's wavelength scan and a reference signal to enable efficient wavelength and intensity calibration using a single reference detector and ADC channel, allowing for simultaneous data acquisition and processing across a wide spectral range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single reference detector and ADC channel are used for calibration, then system complexity and cost are reduced, but calibration efficiency and measurement precision may be compromised
Solution Approach 1:
The patent employs periodic modulation of the laser wavelength scan using trigger signals at specific frequencies. The reference detector output is modulated at a first frequency while the measurement detector output is modulated at a second frequency. This periodic action allows calibration and measurement data to be multiplexed through a single ADC channel by frequency division, reducing system complexity while maintaining calibration precision through frequency-domain separation of signals.
Solution Approach 2:
The patent transitions from time-domain multiplexing to frequency-domain multiplexing by modulating calibration and measurement signals at different frequencies. This dimensional change from temporal to spectral domain allows simultaneous acquisition of calibration and measurement data through a single ADC channel without signal interference, resolving the contradiction between simplified system design and calibration precision.
2Productivity
If high tuning rates are used for fast wavelength scanning, then productivity is improved, but wavelength accuracy and beam quality deteriorate
Solution Approach 1:
The patent uses trigger signals that are synchronized with the laser wavelength scan to provide feedback for wavelength calibration. The reference detector monitors the laser output and generates trigger signals at predetermined wavelength intervals, creating a feedback mechanism that maintains wavelength accuracy even during high-speed scanning. This feedback approach allows fast tuning rates while preserving spectral reproducibility through real-time wavelength reference updates.
Solution Approach 2:
The system performs preliminary wavelength calibration by establishing trigger signal patterns at known wavelength intervals before actual measurement. This preliminary action creates a reference framework that enables subsequent fast scans to maintain accuracy by referencing pre-established wavelength markers, allowing high productivity without sacrificing wavelength precision.
3Measurement precision
If multiple wavelength scans are captured and averaged for statistics, then measurement precision is improved, but measurement time increases
Solution Approach 1:
The patent uses periodic modulation with distinct frequencies for reference and measurement detectors, enabling simultaneous acquisition of calibration and measurement data. This allows single-scan measurements to achieve statistical precision by capturing both calibration reference and sample measurement in the same time frame, eliminating the need for multiple sequential scans and reducing measurement time while maintaining precision.
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 reliable, automated calibration of infrared absorption spectra with reduced system costs and fast data acquisition, decoupling measurement and data processing, and compensating for non-linear detector behavior, even at high measurement rates and low signal intensities.
Implementation Method 1
at least one reference detector in a reference beam path, in which part of the emitted laser light is received and converted into a reference signal
Implementation Method 2
at least one signal detector that receives laser light scattered on the sample and converts it into a measurement signal
Implementation Method 3
at least one tunable laser which is designed for repeatedly irradiating the sample with laser light as a wavelength scan over a defined wavelength range
Implementation Method 4
optical device for capturing infrared absorption spectra of a sample
Data Source
AI summary
An optical device includes a tunable laser for repeatedly irradiating a sample with laser light as wavelength scans over a defined wavelength range, a trigger unit and a data acquisition unit. The laser outputs at least a first trigger signal and a second trigger signal. The first trigger signal outputs a temporal start and a temporal end of a wavelength scan, and the second trigger signal comprises a pattern of scanning pulses distributed over the tunable wavelength range at predefined wavelength intervals. The trigger unit has an adder which adds the trigger signals and a mixer which mixes the trigger signals with the reference signal to form the trigger output signal. A method for capturing infrared absorption spectra is also provided.