Materials design and integration for high-power quantum cascade lasers

Maximum output power and operating temperature of quantum cascade lasers in continuous-wave mode depends strongly on device processing and packaging. Using a combination of epi-side down mounting, metal electroplating, and semiconductor overgrowth, room-temperature cw operation of a QCL at 8 mm was achieved. The threshold current density at 300 K was measured to be 1.83 kA/cm2 in pulsed mode and 3 kA/cm2 in cw mode. The devices emitted up to 5 mW of cw power, and 259 mW peak power in pulsed mode at room temperature.