Abstract
Hydrogen sulfide (H2S) trace gas detection based on off-beam quartz-enhanced photoacoustic spectroscopy using a continuous wave (CW), mode-hop-free external cavity (EC) quantum cascade laser tunable from 1310 to 1210 cm−1 was performed. A 1σ minimum detection limit of 492 parts per billion by volume (ppbv) using a 1 s lock-in time constant was obtained by targeting the line centered at 1234.58 cm−1. This value corresponds to a normalized noise equivalent absorption coefficient for H2S of 3.05 × 10−9 W cm−1 Hz−1/2.
Highlights
The sensitive and selective detection of gaseous sulfur species with the emphasis on hydrogen sulfide (H2S) down to trace concentrations is of essential importance across a wide range of applications including production control and environmental monitoring purposes in the field of petrochemical, paper, and pulp or biotechnological processes
This paper reports on the design and realization of a mid-IR off-beam quartzenhanced photoacoustic spectroscopy (QEPAS) sensor utilizing an MHF ECQCL as the spectroscopic light source for the selective and sensitive detection of H 2S traces
For the selected H 2S absorption line centered at 1234.58 cm−1, the optical power emitted by the MHF external cavity (EC)-quantum cascade lasers (QCLs) was ∼160 mW
Summary
The sensitive and selective detection of gaseous sulfur species with the emphasis on hydrogen sulfide (H2S) down to trace concentrations is of essential importance across a wide range of applications including production control and environmental monitoring purposes in the field of petrochemical, paper, and pulp or biotechnological processes. In the field of laser spectroscopy, the constant improvement of quantum cascade lasers (QCLs) has led to their application as reliable sources of coherent light ranging from the mid-infrared (MIR) to the terahertz spectral region for sensitive detection of molecular species on their fundamental vibrational, respectively, rotational bands [6,7,8,9]. Due to their tailorable emission wavelength, high output power, compactness, narrow spectral linewidth, and wavelength tuneability, QCLs are optimal choices for spectroscopic applications. The external cavity design facilitates broadband spectral tuning by an external diffraction grating, while the selection of the emission wavelength takes place by changing the grating angle relative to the QCL chip
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
