Abstract

Intersubband transitions in semiconductor heterostructures constitute an ideal multi-level system for quantum optical applications. Compared to atomic or molecular systems, the resonances of intersubband structures can be tailored and offer direct electronic control. Moreover, giant transition dipole moments can be designed in the far- infrared, which allows to enter the nonlinear excitation regime at extremely low light intensities. Recently, these properties have stimulated the development of new concepts for photonic signal processing at terahertz frequencies.

© 2002 Optical Society of America