An experimental study of the yellow exciton series in Cu2O in strong magnetic fields up to 32 T shows the optical activation of direct and phonon-assisted paraexciton luminescence due to mixing with the quadruple allowed orthoexciton state. The observed phonon-assisted luminescence yields information on the statistical distribution of occupied states. Additional time-resolved experiments provide a unique opportunity to directly determine the time evolution of the thermodynamical properties of the paraexciton gas. Because the lifetime of paraexciton is hardly affected by the optical activation in a strong magnetic field, this opens new possibilities for studies aiming at Bose-Einstein condensation of excitons in bulk semiconductors.
@article{arxiv.0903.0072,
title = {Magneto-optical readout of dark exciton distribution in cuprous oxide},
author = {D. Fishman and C. Faugeras and M. Potemski and A. Revcolevschi and P. H. M. van Loosdrecht},
journal= {arXiv preprint arXiv:0903.0072},
year = {2009}
}