InAs-based quantum cascade lasers emitting close to 25 µm

Abstract

Indium arsenide (InAs)-based quantum cascade lasers (QCLs) operating close to 25 µm are reported. Thick n-doped InAs cladding layers were used for optical confinement. Fabry-Perot lasers exhibited a threshold current density as low as 1.1 kA/cm 2 in pulsed mode at 80 K. The lasers operated in this regime up to 240 K, where the threshold current density increased up to 1.7 kA/cm 2 . These are the lowest threshold current densities for QCLs operating above 20 µm.