Efficient creation of yellow exciton gas via two photonabsorption to blue excitons in Cu2O

摘要

A new method to produce a high density gas of yellow excitons in Cu2O isreported. The method uses two-photon absorption to high energy blue-excitons as an initialstep. It is shown that the two photon scheme has an improved efficiency over the one- and twophotonexcitation methods used so far. In addition, it has been found that the yellow excitongas produced this way has a significantly enhanced occupation of low momentum states.