We describe a mid-infrared spectrometer that is based on the combination of a multiple-pass absorption cell and a submicrosecond pulsed quantum-cascade laser. The spectrometer is capable of both making sensitive measurements and providing a real-time display of the spectral fingerprint of molecular vapors. For a cell with a path length of 9.6 m, dilution measurements made of the ν9 band transitions of 1, 1-difluoroethylene indicate a sensitivity of 500 parts in 109, corresponding to a fractional absorbance of 4×10-4 .
© 2003 Optical Society of America
E. Normand, M. McCulloch, G. Duxbury, and N. Langford, "Fast, real-time spectrometer based on a pulsed quantum-cascade laser," Opt. Lett. 28, 16-18 (2003)