Lasing in 9.6-μm Quantum Cascade Lasers

Abstract

Lasing in MBE-grown impulsively pumped quantum cascade lasers of 9.6 μm at 140 K has been demonstrated. The active area is based on three-phonon resonance scattering of electrons. An In_0.53Ga_0.47As/Al_0.48In_0.52As solid alloy heteropair was used to form periods of quantum cascade lasers. The upper In_0.52Al_0.48As cladding of the waveguide was made thick. Alloyed and unalloyed lower metallization systems were studied. The threshold current density for a ridge laser 1 mm long and 27 μm wide has been found to roughly equal 3 kA/cm² at 87 K. The optical output power has been estimated at a level of 20–35 mW.