Coupling a Rapid-Scan FT-IR Spectrometer with Quantum Cascade Lasers within a Single Setup: An Easy Way to Reach Microsecond Time Resolution without Losing Spectral Information.

For the first time, a standard rapid-scan Fourier-transform infrared (FT-IR) spectrometer was coupled with quantum cascade lasers (QCLs) tunable within the 1876-905 cm spectral range, within one single setup, by keeping one single sample compartment. The aim was to extend the time resolution of absorption measurements by several orders of magnitude thanks to the fast pulsed QCL technology without losing the spectral information provided by standard FT-IR spectroscopy, both probing the same sample. By slightly modifying the optical bench arrangement, the spectrometer now enables a fast and easy switch between the standard FT-IR mode, used for classical broadband scans from 6000 to 650 cm, and the new QCL-irradiation mode, used for ultrafast recording at specific wavenumbers (the two diagnostics have superimposed beam paths).