A study of exciton lifetimes in cuprous oxide using tunable dye lasers

A pulsed tunable dye laser and a continuous wave dye laser were used to study the dominant decay mechanisms for the 1S yellow exciton in cuprous oxide. These decay channels are acoustical phonon absorption and emission and nonradiative decay. A direct decay time measurement using the pulsed laser indicated a subnanosecond lifetime. The natural linewidth of the exciton state corresponding to direct photon absorption was determined by the Raman enhancement profiles near resonance with this exciton state. The temperature dependence of this linewidth was calculated. The results indicate a total exciton lifetime of 3 x 10 to the -11th power seconds for zero momentum and lattice temperatures near 6 K. The observed lifetimes and calculated momentum dependence are then applied to an analysis of three separate experiments.