  When a semiconductor absorbs light, the resulting electron-hole superposition
amounts to a uncontrolled quantum ripple that eventually degenerates into
diffusion. If the conformation of these excitonic superpositions could be
engineered, though, they would constitute a new means of transporting
information and energy. We show that properly designed laser pulses can be used
to create such excitonic wave packets. They can be formed with a prescribed
speed, direction and spectral make-up that allows them to be selectively
passed, rejected or even dissociated using superlattices. Their coherence also
provides a handle for manipulation using active, external controls. Energy and
information can be conveniently processed and subsequently removed at a distant
site by reversing the original procedure to produce a stimulated emission. The
ability to create, manage and remove structured excitons comprises the
foundation for opto-excitonic circuits with application to a wide range of
quantum information, energy and light-flow technologies. The paradigm is
demonstrated using both Tight-Binding and Time-Domain Density Functional Theory
simulations.
