Publications

Terahertz quantum-cascade laser operating up to 137 K

Williams, Benjamin S.; Kumar, Sushil; Callebaut, Hans; Hu, Qing; Reno, J.L.

The operation of a tetrahertz quantum-cascade laser at 3.8 THz (λ= 79 μm) up to a heat sink temperature of 137 K was presented. A resonant phonon depopulation design was used with a low-loss metal-metal waveguide, providing a confinement factor of nearly unity. A threshold current density of 625 A/cm 2 was found in pulsed mode at 5 K. It was found that a thicker barrier reduced the coupling between the injector state and the excited state in the wide well of the module, which was caused by the parasitic current channel.