Linear cavity optical-feedback cavity-enhanced absorption spectroscopy with a quantum cascade laser.
A cw distributed feedback quantum cascade laser (DFB-QCL) coupled to a two-mirror linear optical cavity has been used to successfully demonstrate optical-feedback cavity-enhanced absorption spectroscopy (OF-CEAS) at 5.5 μm. The noise-equivalent absorption coefficient, α(min), was 2.4×10(-8) cm(-1) for 1 s averaging, limited by etalon-fringing. The temporal stability of the instrument allows NO detection down to 5 ppb in 2 s.
Department of Chemistry, The Physical and Theoretical Chemistry Laboratory, The University of Oxford, Oxford, UK.
A G V
AG
Bergin
G
G
Hancock
G A D
GA
Ritchie
D
D
Weidmann