Prediction of pure electric-dipole two-photon absorption circular dichroism in lanthanide compounds Original Research Article

Standard theories of chiral linear and nonlinear optical effects, such as circular intensity differentials and optical activity, require interference between electric-dipole and magnetic-dipole (or higher-order) contributions to the transition moments. Recent experimental and theoretical work on second-harmonic generation processes has shown that in the resonant case, pure electric-dipole contributions to such chiral effects are possible. In this paper, we consider the implications of pure electric-dipole contributions to circular dichroism in two-photon absorption transitions within the 4fN configuration of lanthanide ions. We show that in some lanthanide compounds, when several intermediate states are near to resonance, the pure electric-dipole mechanism can give larger contributions than the standard electric-dipole magnetic-dipole mechanism.