A theoretical study of quantum well terahertz lasers

A theoretical study is made of a GaAs/AlGaAs triple quantum well structure with the aim of developing a three level laser to emit in the terahertz region of the spectrum. The population inversion necessary for laser emission to take place is estimated by calculating the net nonradiative transition rates. It is found that the most effective way of achieving a population inversion is by depopulation to a strongly coupled state. The population inversion can be increased further by decreasing the barrier width between the quantum wells associated with the two lowest energy levels