Ultrafast All Optical Switching via Tunable Fano Interference

Tunneling induced quantum interference experienced by an incident probe in asymmetric double
quantum wells can easily be modulated by means of an external control light beam. This phenomenon,
which is here examined within the dressed-state picture, can be exploited to devise a novel all-optical
ultrafast switch. For a suitably designed semiconductor heterostructure, the switch is found to exhibit
frequency bandwidths of the order of 0.1 THz and response and recovery times of about 1 ps.