Answers are grounded in this paper and cite their sources.
Experimental study reveals enhanced photoacoustic signal generation via combined amplitude and wavelength modulation in ammonia sensing, indicating improved spectroscopic detection efficiency.
Photoacoustic (PA) spectra generated by current modulation of a distributed feedback diode laser (DFB-DL) were measured for the ammonia absorption line at 1.53 microm and calculated using absorption spectra taken from a database. The algorithm is based on a combined amplitude- and wavelength-modulation (AM-WM) scheme. The spectral characteristics of the DFB-DL were determined by comparing simulated spectra with Fourier transform infrared measurements. PA spectra were measured and simulated from the first to fourth harmonic and a variation of the modulation depth with modulation frequency was observed. It was found that combined AM-WM modulation may produce larger PA signals than separate AM or WM detection for the first harmonic.
No takes yet. Share an insight, caveat, or question.
Angelmahr et al. (2008) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: