Strongly Modulated Quantum Cascade Lasers for Broadband and Fast Doppler-Based FTIR Spectroscopy

The possibility of making reliable, fast and broadband spectroscopy in the Mid-IR region is extremely appealing, and it goes in hand with the availability of suitable light-sources. Here we prove that, by strongly RF modulating a Mid-Infrared Quantum Cascade Laser at low injection frequency compared to its natural repetition frequency it is possible to double its emission bandwidth up to 250. In addition, we show it can be used in combination with a Doppler based FTIR, opening the possibility to fast and broadband FTIR spectroscopy.