Quartz-enhanced photoacoustic spectroscopy sensor for ethylene detection with a 3.32 μm distributed feedback laser diode.

An antimonide distributed feedback quantum wells diode laser operating at 3.32 μm at near room temperature in the continuous wave regime has been used to perform ethylene detection based on quartz enhanced photoacoustic spectroscopy. An absorption line centered at 3007.52 cm(-1) was investigated and a normalized noise equivalent absorption coefficient (1σ) of 3.09 10(-7) cm(-1) W Hz(-1/2) was obtained. The linearity and the stability of the detection have been evaluated. Biological samples' respiration has been measured to validate the feasibility of the detection setup in an agronomic environment, especially on ripening apples.