  We have performed angle resolved photoemission spectroscopy (ARPES)
experiments on the surface states of SrTiO$_3$(001) using linearly and
circularly polarized light to investigate the subband structures of
out-of-plane $d_{xz/yz}$ orbitals and chiral orbital angular momentum (OAM).
The data taken in the first Brillouin zone reveal new subbands for $d_{xz/yz}$
orbitals with Fermi wave vectors of 0.25 and 0.45 $\mathrm{\AA}^{-1}$ in
addition to the previously reported ones. As a result, there are at least two
subbands for all the Ti 3d t$_{2g}$ orbitals. Our circular dichroism ARPES data
is suggestive of a chiral OAM structure in the surface states and may provide
clues to the origin of the linear Rashba-like surface band splitting.
