Dynamic control of coherent pulses via Fano-type interference in asymmetric double quantum wells

We study the temporal and spatial dynamics of two light pulses, a probe and a switch, propagating through
an asymmetric double quantum well where tunneling-induced quantum interference may be observed. When
such an interference takes place, in the absence of the switch, the quantum well is transparent to the probe
which propagates over sufficiently long distances at very small group velocities. In the presence of a relatively
strong switch, however, the probe pulse is absorbed due to the quenching of tunneling-induced quantum
interference. The probe may be made to vanish even when switch and probe are somewhat delayed with
respect to one another. Conversely, our asymmetric double quantum well may be rendered either opaque or
transparent to the switch pulse. Such a probe-switch “reciprocity” can be used to devise a versatile all-optical
quantum interference-based solid-state switch for optical communication devices.