Electron-lattice coupling in bound-to-continuum THz quantum-cascade lasers

We measured the thermal resistance (R=20.1K∕W) and the electrical power dependence of the electronic temperature (Re=27.0K∕W) of THz quantum-cascade lasers (QCLs) with bound-to-continuum active region scheme in the lattice temperature range of 30–100K. This information, obtained from the analysis of microprobe photoluminescence spectra for QCLs operating at 2.5THz, gives an electron-lattice energy relaxation rate (0.1ps−1) ∼50 times lower than THz QCLs with resonant-phonon active region scheme.