Transmission Characteristics of Waveguide-Coupled Nanocavity Embedded in Two Atoms with Dipole-Dipole Interaction

Photon scattering properties in one-dimensional waveguide side coupled to a nanocavity embedded in two atoms with dipole-dipole interaction （DDI） are investigated theoretically. The analytical expressions of the transmission and reflection amplitudes are deduced by using the real-space Hamiltonian. A method to determine the coupling strength of DDI is proposed. Realization of single photon switching by modulation the DDI is investigated. The influence of dissipations on the performance of the single photon switching are exhibited. An asymmetric Fano-type resonance, which can be controlled by the DDI, appears in the transmission spectrum.     

Second-Order Correlation Function of the Photon Emission from a Single Quantum Dot

The photon correlation of photon emission from a single quantum dot with cw excitation and pulsed excitation is investigated in details. To calculate the second-order correlation function for optical pumping, we deduce rate equations with a simplified two-level model under cw excitation and present the master equation approach in the interaction picture to the study of evolution of a three-level system under pulsed excitation. In addition, we report photon correlation measurements on a single self-assembled In0.5Ga0.5As quantum dot, which show strong antibunching behaviour under both the conditions of cw and pulsed excitations. The calculated results are in agreement with the experimental measurements.     

Nonreciprocal Single Photon Frequency Conversion via Chiral Coupling between a V-Type System and a Pair of Waveguides

The single photon frequency conversion is investigated theoretically in the system composed of a V-type system chiral coupling to a pair of waveguides. The single photon scattering amplitudes are obtained using the real-space Hamiltonian. The calculated results show that the probability of single photon frequency down-or up-conversion can reach a unit by choosing appropriate parameters in the non-dissipative system with perfect chiral coupling.We present a nonreciprocal single photon beam splitter whose frequency of the output photon is different from that of the input photon. The influences of dissipations and non-perfect chiral coupling on the single frequency conversion are also shown. Our results may be useful in designing quantum devices at the single-photon level.     

Polarization Conversion of Single Photon via Scattering by a Λ System in a Semi-Infinite Waveguide

We theoretically investigate single-photon polarization conversion via scattering by an atom with Λ configuration coupled to a semi-infinite waveguide and discuss the two cases in which the Λ system is non-degenerated and degenerated. By applying the hard-wall boundary condition of the semi-infinite waveguide, it is found that singlephoton polarization conversion can be realized with unit probability for both cases under the ideal condition.Together with the polarization conversion, the frequency conversion of a single photon can also be realized with unit probability in the ideal case if the Λ system is not degenerated.