Generation of a single-photon source via a four-wave mixing process in a cavity

It is shown that an efficient, well-directional single-photon source can be realized via a four-wave mixing process in a cavity. The probability of producing a single-photon state nearly approaches 50%. The bandwidth of single-photons generated in this way is controllable, which is determined by that of the input pulse. Furthermore, we propose a scheme to generate a coherent multichannel single-photon source, which might have significant applications in wavelength division multiplexing quantum key distribution.

Figure 1

(Color online) Schematic diagram of generation of a single-photon source.

Figure 2

(Color online) Conversion between the pump field and the idler field.

Figure 3

(Color online) The probability evolution of 6 states for initial Fock state ${|5⟩}_p$ case. $\gamma =1$ and $\eta =0.1$.

Figure 4

(Color online) The probability evolution of the one-photon (solid lines) and vacuum (dashed lines) states for initial coherent state case. $\left|\alpha \right|=1.5$, $\gamma =1$, and $\eta =0.1$.

Figure 5

(Color online) The evolution from $|5_p⟩$ to $|1_p⟩$ with different $\eta$. $\gamma =1$.

Figure 6

(Color online) Scheme for a coherent multifrequency single-photon emitter.

Figure 7

(Color online) A proposal for WDM-QKD at true single-photon level.