Cantilever-enhanced photoacoustic detection of hydrogen sulfide (H2S) using NIR telecom laser sources near 1.6 μm

Sensitive detection of hydrogen sulfide (H2S) at different pressure levels using a cantilever-enhanced photoacoustic detector in combination with a telecom NIR L-band laser source is reported. Amplitude and wavelength modulation schemes for photoacoustic signal generation are compared. A detection limit (3 sigma) of 8 ppmv was achieved for amplitude modulation mode with a 50-s averaging time for the H2S absorption near 1.6 mu m. As compared to simulated spectra, the cantilever-enhanced photoacoustic detection approach in combination with the sufficiently stable and narrow bandwidth NIR laser is able to reproduce the rotationally resolved H2S spectrum at low pressures of 300 mbar.