Enhancing the detection probability of single waveguided-photon by   cavity technique
  The resonant-cavity-enhanced (RCE) technique is an important approach to increasing the detection efficiency (DE) of typical free-space coupling photons. Here, we show that such a technique can also be utilized to increase the detection probability (DP) of a single waveguide-coupled photon. Based on a fully quantum mechanical theory in real space, we exactly calculated the absorption probability of a single photon for a two-level detector next to the waveguide. We find that the DP of the waveguide photon for the detector in a waveguide-coupled ring cavity is significantly higher than that for the bare detector directly coupled to the photon. Physically, the DP of the photon for the bare detector next to the waveguide is always limited by the finite transmission and reflection probabilities of the photon. The cavity technique is used to store the photon and thus increase its DP. The feasibility of the proposal with current integrated optical devices is then discussed. 
L. Y. Xie and L. F. Wei
quant-ph