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.
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.
For the first time, to the best of our knowledge, we investigate the photonic band gap (PBG) structure through scanning the frequency detunings of the probe field, the dressing field, and the coupling field in the static and moving electromagnetically induced grating (EIG) field. When we scan the frequency detuning of the coupling field, the PBG structure and six-wave-mixing band gap signal (SWM BGS) appear at the right of the electromagnetically induced transparency (EIT) position. But the PBG structure and SWM BGS appear at the left of the EIT position in the case of scanning the probe field frequency detuning. Also, on the condition of scanning the probe field frequency detuning, the SWM BGS appears in two frequency ranges. Moreover, in the moving PBG structure, nonreciprocity of the SWM BGS can be obtained. Furthermore, the intensity, width, and location of the SWM BGS can be modulated through changing the frequency detunings and intensities of the probe field, the dressing field, and the coupling field; the sample length; and the frequency difference of coupling fields in EIG. Such a scheme could have potential applications in optical diodes, amplifiers, and quantum information processing.
The dressed four-wave mixing (FWM) in a four-level 85 Rb atomic system, experimentally demonstrated in this paper, is comprised by two coexisting processes. One is emission signal due to enhanced nonlinear via electromagnetically induced transparency (EIT). The other is the Bragg reflection of probe beam because of the created photonic band gap (PBG), which is affected by both linear and third-order nonlinear susceptibility. Moreover, we have demonstrated that different experimental parameters can significantly influence the measured signal with flexibly controlled PBG. These studies are found useful for understanding the fundamental mechanisms in generated FWM processing.
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.
We experimentally investigate probe transmission signals (PTS), the four-wave mixing photonic band gap signal (FWM BGS), and the fluorescence signal (FLS) in an inverted Y-type four level atomic system. For the first time, we compare the FLS of the two ground-state hyperfine levels of Rb 85. In particular, the second-order and the fourth-order fluorescence signals perform dramatic dressing discrepancies under the two hyperfine levels. Moreover, we find that the dressing field has some dressing effects on three such types of signals. Therefore, we demonstrate that the characteristics of PTS, FWM BGS, and FLS can be controlled by frequency detunings, the powers or phases of the dressing field. Such research could have potential applications in optical diodes, amplifiers, and quantum information processing.
We mainly investigate four generated four-wave-mixing (FWM) signals, and second- and fourth-order fluorescence (FL) signals, simultaneously in a cascade three-level atomic system of sodium, in which dual electromagnetically induced transparency windows are used to enable transparency of the generated FWM signals. The moving and immobile two-photon dressing effects on the FWM and multi-order FL signals as well as the interaction of dressing effects are studied. Furthermore, we investigate the spontaneous parametric FWM signal and spatial images of the transmitted probe signal modulated by the cross-Kerr nonlinearities effect of the dressing field both experimentally and theoretically. The study may find applications in all-optical communication.
We investigate the spatial images of the probe, generated four wave mixing (FWM) signal and the accompanying fluorescence spectrum signal simultaneously in FWM process in a cascade three-level atomic system for the first time. We experimentally observe and theoretically investigate the three spectrum signals versus the probe field as well as the dressing field frequency detunings. Utilizing the experimental results of spectrum signals, the cross phase modulation and the relative position between the weak and strong beams, we analyze the characteristics indicated in the spatial images of probe transmission and FWM, such as focusing or defocusing, shift and splitting in detail. Such studies can be used in all-optical controlled spatial signal transmission.