Far-infrared stimulated emission tunable by modulation of acoustic phonon scattering in quantum dot structures

We propose a new mechanism for far-infrared (FIR) stimulated emission in qu antum dot structures with gain and emission frequency modulated by acoustic phonon scattering. This novel mechanism is based on carrier injection into coupled quantum dot structures in the Wannier-Stark localization regime fo r which current oscillates due to Bragg reflection of acoustic phonons. The population inversion is achieved by engineering the quantum dot coupling a nd the collector tunnel barrier such that the tunnelling times fall in the range of the acoustic phonon scattering time. Realistic estimates of the ga in show that FIR stimulated emission with reasonable current injection is f easible.