Ultra-high sensitive acetylene detection using quartz-enhanced photoacoustic spectroscopy with a fiber amplified diode laser and a 30.72 kHz quartz tuning fork

An ultra-high sensitive acetylene (C2H2) Quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor based on a high power laser and a quartz tuning fork with a resonance frequency f0 of 30.72 kHz was demonstrated. An erbium-doped fiber amplifier (EDFA) amplified distributed feedback diode laser with a center wavelength of 1.53 μm was used as the exciting source. A 33.2 ppb minimum detection limit (MDL) at 6534.37 cm−1 was achieved, and the calculated normalized noise equivalent absorption coefficient was 3.54 × 10−8 cm−1 W/√Hz when the laser output power was 1500 mW. The ppb-level detection sensitivity of C2H2 validated the reported QEPAS method.