Suppression and enhancement of coexisting super-fluorescence and multi-wave mixing processes in sodium vapor

Interplay between six wave mixing photonic band gap signal and second-order nonlinear signal in electromagnetically induced grating

For the first time, we experimentally and theoretically research about the second-order nonlinear signal (SNS) including electromagnetically induced absorbing (EIA) and electromagnetically induced gain (EIG), six wave mixing band gap signal (SWM BGS) resulting from photonic band gap structure in an inverted Y-type four level system with the electromagnetically induced grating. The interplay between the SNS and SWM BGS is illustrated clearly for the first time. When we change the frequency detuning to make the SWM BGS and SNS overlap, the SWM BGS is suppressed and the intensity of SNS is strongest near the resonance point. We can control the intensity of the SWM BGS and EIG caused by the classic effect through changing the power of coupling field. And the changes on the EIA generated by the quantum effect are obtained by changing the power of dressing field. Since the SWM BGS is the enhancement of the four wave mixing band gap signal (FWM BGS), when we set FWM BGS as the input and SNS as the modulation role to control the amplification amplitude for the FWM BGS in our scheme, the adjustable optical amplifier can be obtained.

Observation of the four wave mixing photonic band gap signal in electromagnetically induced grating

For the first time, we experimentally and theoretically research about the probe transmission signal (PTS), the reflected four wave mixing band gap signal(FWM BGS) and fluorescence signal (FLS) under the double dressing effect in an inverted Y-type four level system. FWM BGS results from photonic band gap structure. We demonstrate that the characteristics of PTS, FWM BGS and FLS can be controlled by power, phase and the frequency detuning of the dressing beams. It is observed in our experiment that FWM BGS switches from suppression to enhancement, corresponding to the switch from transmission enhancement to absorption enhancement in the PTS with changing the relative phase. We also observe the relation among the three signals, which satisfy the law of conservation of energy. Such scheme could have potential applications in optical diodes, amplifiers and quantum information processing.

Rydberg dressing evolution via Rabi frequency control in thermal atomic vapors

We report for the first time the theoretical and experimental research on Rydberg electromagnetically induced transparency and second-order fluorescence dressing evolution by Rabi frequency control in thermal atomic vapors, in which the controlled results are well explained by the dressing effect and the Rydberg excitation blockade. Based on the certification of the Rydberg excitation blockade fraction through the dependence on principle quantum number n, we obtain dressing evolution curves, consisting of single-dressing and double-dressing in local and nonlocal blockade samples by scanning the probe and dressing fields. In addition, the competition between the Rydberg dressing second-order fluorescence and fourth-order fluorescence is first investigated. A corresponding theory is presented, which is consistent with the experimental results. Such blockade evolution regularity has potential applications in quantum control, and the Rydberg dressing may be useful for investigating multiple-body interactions, as well as for inducing short range interactions in Bose-Einstein condensates.