Excitation dynamics in a three-quantum dot system driven by optical near-field interaction: towards a nanometric photonic device.

Using density operator formalism, we discuss interdot excitation energy transfer dynamics driven by the optical near-field and phonon bath reservoir, as well as coherent excitation dynamics of a quantum dot system. As an effective interaction between quantum dots induced by the optical near-field, the projection operator method gives a renormalized dipole interaction, which is expressed as a sum of the Yukawa functions and is used as the optical near-field coupling of quantum dots. We examine one- and two-exciton dynamics of a three-quantum dot system suggesting a nanometric photonic switch, and numerically obtain a transfer time comparable with the recent experimental results for CuCl quantum dots.

A method for controlling the spins of atoms using optical near-fields.

On the basis of the procedure for controlling the spins of atoms using circularly polarized evanescent light proposed by Hori et al.[(1996) Abstracts of the 1st Asia-Pacific Workshop on Near-field Optics] we discuss the influence of boundary conditions on the probability of spontaneous emission and thus on the spin polarization efficiency, which was not considered in the Hori et al. study. Using the Carniglia-Mandel mode expansion of electromagnetic fields, we derive the spontaneous emission and spin polarization probabilities of atoms near a dielectric surface, and show the atom-surface distance dependence and refractive index dependence. Numerical evaluation for the 6P1/2-6S1/2 transition of a Cs atom indicates an increase in the efficiency of spin polarization by 30%.