Controllable single-photon frequency converter via a one-dimensional waveguide

We propose a single-photon frequency converter via a one-dimensional waveguide coupled to a three-level V-type atom. An on-demand classical driving field is used to couple to the atom, allowing it to absorb a photon with a given frequency and then emit a photon with a different carried frequency. We study such a single-photon frequency conversion mechanism in two kinds of realistic physical systems: the system of coupled-resonator waveguide with cosine dispersion relation and the one of waveguide with linear dispersion relation. To demonstrate the single-photon transfer efficiency, we introduce the concept of scattering flows via the calculation of group velocities and find that the driving field prefers to be weak in the coupled-resonator waveguide but arbitrarily strong in the linear waveguide to achieve an optimal transfer efficiency. Furthermore, we demonstrate that our theoretical model is experimentally feasible with currently available technologies.