Room Temperature Lasing of Terahertz Quantum Cascade Lasers Based on a Quantum Dot Superlattice

We investigate room temperature lasing of terahertz quantum cascade lasers using quantum dot chains as active material. Bandstructure calculations for such extended systems of coupled quantum dots are made possible by a novel "linear combination of atomic orbitals"-like approximation, based on single quantum dot wavefunctions. Our results demonstrate that terahertz quantum cascade lasers greatly benefit from intrinsic properties of quantum dots, such as reduced phonon coupling and in-plane scattering, enabling room temperature lasing with significantly reduced threshold current densities.