Phonon engineered quantum cascade terahertz emission

The observation of terahertz (THz) intersubband emission from GaAs/AlGaAs quantum cascade structures employing higher energy interface and barrier confined AlAs-like phonons for depopulation is reported. Emission is observed at View the MathML sourceView the MathML source and View the MathML sourceView the MathML source with full-width at half-maximum of 0.7 and View the MathML source, respectively, at View the MathML source from two different structures. The structures consisted of 40 periods of the quantum cascade module and relied on spatially diagonal (interwell) transition for the terahertz emission. The possibility of tuning the emission frequency using quantum confined Stark effect is also demonstrated.