Propagating multi-channel four-wave mixing process in the modulated moving photonic band gap

Three and four electromagnetically induced transparency windows generate the multi-channel four-wave mixing (FWM) process are observed in a four-level atomic system. The transmission of the probe field and the reflection of the FWM are investigated in the modulated moving photonic band gap structures which are caused by the coupling fields with a relative small detuning offset when scanning detuning frequency of the probe field and the dressing field, respectively. The experimental results show that the more channels spectrum signal of the FWM process can be modulated and the generated multi-channel can be further modulated by adding a dressing field. We have also explained theoretically these experimental results which may have applications in the design of photonic crystal and optical signal amplifiers.