Pulse Wavelength Scan of Room-Temperature Mid-Infrared Distributed Feedback Quantum Cascade Lasers for N₂O Gas Detection

The tunable diode laser absorption spectroscopy under a pulse wavelength scan scheme is adapted to home-made room-temperature mid-infrared distributed feedback quantum cascade lasers; and identification of N₂O spectral fingerprint is demonstrated experimentally. By driving the laser at 800ns pulse duration, a wave number tuning of about 1.6cm^-1 is produced, which make both 1289.04cm^-1 and 1289.86cm^-1 absorption fingerprints of N₂O gas to be definitely assigned. The measured relative absorption intensity is consistent with the HITRAN data precisely.