Opening optical four-wave mixing channels with giant enhancement using ultraslow pump waves

An overview is given on the first theoretical investigation of optical coherent four-wave mixing (FWM) with a weak pump wave that travels with an extremely slow group velocity. Two key contributions are presented. First, it is shown that the electromagnetically induced transparency (EIT) window created by a coupling laser drastically modifies the dispersion properties for a pump wave traveling in the medium, and opens a coherent four-wave mixing (FWM) production. Second, it is illustrated that contrary to common belief, a wider trasparency window, resulting in less loss and higher propagation velocity for the pump wave, actually significantly diminishes the coherent FWM efficiency.