Self-Induced Transparency Modelocking of Quantum Cascade Lasers

The possibility of using the self-induced transparency effect to passively modelock lasers has been discussed since the late 1960s, but has never been observed. It is proposed that quantum cascade lasers are the ideal tool to create this modelocking, due to their rapid recovery times and relatively long coherence times and because it is possible to interleave gain and absorbing layers. Conversely, it is possible to use the self-induced transparency effect to create midinfrared pulses that are less than 100 fs in duration in a semiconductor laser.