InP based, terahertz quantum cascade lasers with 4 quantum well active region design

The quantum cascade laser (QCL) is a semiconductor laser that employs radiative transitions of an electron between the bounded states in a superlattice (SL) and phenomenon of resonant tunnelling. Here we present a QCL that operates in the terahertz (THz) spectral region at wavelength of 95µm. Important difference compared to previous terahertz QCL's based on GaAs/AlGaAs material system is choice of In
0.47
Ga
0.53
As/In
0.48
Al
0.52
As lattice matched to InP which has lighter electron effective mass that should lead to higher gain and better operation [1].