  We perform an optimal-observable analysis of the final charged-lepton/b-quark
momentum distributions in gamma+gamma -> t+tbar -> lX/bX for various beam
polarizations in order to study possible anomalous t-tbar-gamma, tbW and
gamma-gamma-H couplings, which could be generated by SU(2)xU(1) gauge-invariant
dimension-6 effective operators. We find optimal beam polarizations that will
minimize the uncertainty in determination of those non-standard couplings. We
also compare e+ebar and gamma+gamma colliders from the viewpoint of the
anomalous-top-quark-coupling determination.
