  The optical transitions between spin-polarized bands of the quasi-two
dimensional Rashba system BiTeI are investigated using polarization resolved
resonant Raman spectroscopy. We detect chiral excitations between states with
opposite helicity and compare spectra to calculations within a three-band
model. Using the resonant Raman excitation profile, we deduce the Rashba
parameters and band gaps of the higher conduction bands near the Fermi level,
and compare the parameters to values obtained by ab initio density function
theory (DFT).
