  A description of spin Faraday rotation, Kerr rotation and ellipticity signals
for single- and multi-layer ensembles of singly charged quantum dots (QDs) is
developed. The microscopic theory considers both the single pump-pulse
excitation and the effect of a train of such pulses, which in the case of long
resident-electron spin coherence time leads to a stationary distribution of the
electron spin polarization. The calculations performed for single-color and
two-color pump-probe setups show that the three experimental techniques:
Faraday rotation, Kerr rotation and ellipticity measurements provide
complementary information about an inhomogeneous ensemble of QDs. The
microscopic theory developed for a three-dimensional ensemble of QDs is shown
to agree with the phenomenological description of these effects. The typical
time-dependent traces of pump-probe Faraday rotation, Kerr rotation and
ellipticity signals are calculated for various experimental conditions.
