  Resonant photoluminescence excitation (RPLE) spectra of a neutral InGaAs
quantum dot show an unconventional line-shape that depends on the detection
polarization. We characterize this phenomenon by performing
polarization-dependent RPLE measurements and simulating the measured spectra
with a 3-level quantum model. This analysis enables us to extract the coherence
between the two exciton states from the measured spectra. The good agreement
between the data and model indicates that the interference between coherent
scatterings from both fine structure split exciton states is the key to
understanding this phenomenon.
