[Tunable Diode Laser Absorption Spectroscopy (TDLAS) Detection Signal Denoising Based on Gabor Transform]

Area of Science:

• Spectroscopy
• Laser Technology
• Chemical Sensing

Background:

• Tunable diode laser absorption spectroscopy (TDLAS) combined with wavelength modulation spectroscopy (WMS) is crucial for trace gas detection.
• The second harmonic signal, essential for gas absorption analysis, is susceptible to noise, reducing system accuracy and stability.

Purpose of the Study:

• To propose and validate a Gabor transform-based denoising method for reducing noise in the second harmonic signal of TDLAS systems.
• To enhance the signal-to-noise ratio (SNR), accuracy, and stability of trace gas detection.

Main Methods:

• Utilized Gabor transform for noise reduction on the second harmonic signal in TDLAS.
• Simulated and experimentally verified the method using the CH4 absorption spectrum at 1653.72 nm.

Main Results:

• Gabor transform denoising improved the SNR of the second harmonic signal by 15.73 dB in simulations.
• Experimental results showed a high linear correlation (r=0.99659) between the second harmonic peak and CH4 concentration (0.001%-0.02%).

Conclusions:

• The Gabor transform-based denoising method effectively reduces noise in TDLAS systems.
• This technique significantly improves detection accuracy and stability for trace gas analysis, particularly for methane.