Optical excitation of a semiconductor crystal at low temperature produces mobile electrons and holes which combine to form short lived excitons. Because of their light mass, excitons are candidates for a novel quantum effect called Bose-Einstein Condensation (BEC). Under intense pulsed laser excitation at low temperature, excitons in high-purity single crystals of CU2O display properties characteristic of quantum statistics leading to BEC. The present studies will create and probe this unusual system to examine the relaxation kinetics and to attempt to produce BEC. To conditions for observation will be optimized by applying stress and magnetic fields to the crystal. Strain-confinement and sub-Kelvin temperature will be used to produce long-lived quantum exciton gas and allow the possibility of observing ballistic propagation of excitons over macroscopic distances.
