High-efficiency four-wave mixing in a five-level atomic system based on two-electromagnetically induced transparency in the ultraslow propagation regime

We have analyzed a five-level Lambda-configuration four-wave mixing (FWM) scheme for obtaining high-efficiency FWM based on the two-electromagnetically induced transparency (EIT) in the ultraslow propagation regime. We find that the maximum FWM efficiency is nearly 30%, which is orders of magnitude larger than previous schemes based on the two-EIT. Our scheme allows the possibility for new technological applications such as nonlinear spectroscopy at very low light intensity, quantum single-photon nonlinear optics and quantum information science.