Parametrical amplification induced nonreciprocity in photonic band gaps

For the first time, we experimentally investigate the parametrically amplified nonreciprocity of the transmission of the probe field, the reflection of the suppressed four-wave mixing (FWM), the enhanced six-wave mixing (SWM) and the radiation trap nonreciprocity of the fluorescence signals in a five level atomic system. The transition from the dressed suppressed dip to the enhanced peak is due to the nonreciprocity induced by parametrical amplification which is observed in FWM (SWM) signals noticeably. The SWM signal exhibits more obvious nonreciprocity than the FWM signal because the former suffers significant dressing enhancement. Moreover, the frequency offset of the signals on the two arm ramps of one round trip results from the optical bistability (nonreciprocity) which can be controlled by the frequency detunings, powers and angles of the dressing fields. Such a scheme could have potential applications in amplification processing of transistors and quantum information processing.