  A new generalised group-theoretical approach, based on master
Maxwell-pseudospin equations, is proposed to explain recently observed enhanced
circular dichroism in the excited state emission from p-doped quantum dot
ensembles under resonant circularly polarised excitation into hot trion states,
herein referred to as "spin-filtering effect". The theory agrees remarkably
well with polarised time-resolved photoluminescence experiments, yielding
largely unknown inter- and intra-shell spin relaxation time scales. This
approach allows to predict optimum pulse parameters for control of spin
dynamics, which will enable exploitation of the effect in all-optical
spin-based quantum technologies.
