Slow and stored light in amplifying four way mixing process

We have investigated experimentally and theoretically four-wave mixing (FWM) in hot potassium vapor as a medium for producing slow and store light. Two pump and a single probe photon were mixed in double-Λ system, characterized by parametric amplification of coupled co-propagating probe and conjugate beams. We have observed very high gains of probe and conjugate, up to 60 and 80 respectively, at two photon Raman resonance, under large one photon detuning, and high K-cell temperature. Using an amplifying medium to alleviate the absorption and distortion of propagating pulses are important for slow-light propagation. We observed ultraslow propagation of probe and conjugate pulses under conditions when parametric amplification of twin beams is well below their maximum values. A fractional delays of close to 5 at a gain ∼1.5, for the probe pulse of 20 ns, have been achieved simultaneously for both probe and accompanying conjugate pulse. FWM mixing process under conditions of the experiment results in broadening of twin beams, close to observed delays.