Cooling of excitons by coherent phonon radiation

The effect of exciton cooling by coherent phonon radiation, which is based on coherent confinement of exciton populations, is considered. Peculiarities of coherent confinement of excitons in an exciton system are analyzed, in which the umklapp processes as well as recombination and relaxation play an important role. The limitations imposed on the parameters of the system for which the effect can be realized are determined taking into account these peculiarities.