Prospects of temperature performance enhancement through higher resonant phonon transition designs in GaAs-based terahertz quantum-cascade lasers

In this work we discuss terahertz quantum cascade laser designs that employ resonant phonon mechanism to assist the lasing process. We investigate whether the higher energy separation would be more beneficial for high temperature performance than commonly used resonant value of 36 meV (in GaAs). We show that our density matrix model can be used for reliable cut–off temperature estimation and we present design improvement of several exemplary structures by enhancing their material gain to attain 10 - 50 K higher cut–off temperature