Low threshold room temperature GaAs/AlGaAs quantum cascade laser with InAlP waveguide

A λ≃9.7λλm GaAs/Al_0.45Ga_0.55As quantum cascade laser with an In_0.47Al_0.53P waveguide is reported that demonstrates record low threshold current densities for the GaAs/Al_xGa_1-xAs materials system in the mid-infrared. Under pulsed operation, threshold current densities of 2.2 and 4.4 kA/cm² are observed at 240 and 300 K, respectively, and laser emission is maintained up to temperatures of at least 330 K. The laser was grown by metal-organic vapour phase epitaxy, and emits peak optical powers of up to 0.57 W at 240 K and 0.16 W at 300 K.