Observation of giant gain and coupled parametric oscillations between four optical channels in cascaded four-wave mixing

Lopez, J. P.; Melo, A. M. G. de; Felinto, D.; Tabosa, J. W. R.

doi:10.1103/physreva.100.023839

Cited by 8 publications

(3 citation statements)

References 28 publications

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“…The threshold-like nature of isotropic blue light intensity w.r.t detuning from exact two-photon resonance (cf figure 6(A), (B)) indicates this onset of ASE. Lopez et al [41] also reported this threshold nature for coupled parametric oscillation earlier. However, variable detuning at constant laser intensity changes generalized Rabi frequency [42].…”

Section: Resultsmentioning

confidence: 69%

Two-photon coherence in a DROP-FWM medium

Shukla,

Ray

2024

Phys. Scr.

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In this work, we report experimental studies on coherence in a medium exhibiting DROP (Double Resonance Optical Pumping)-FWM (Four Wave Mixing). Here 5S1/2(F) → 5P3/2(F/) → 5D (F//) two photon transition of hot 87Rb atoms is used. The 5S→5P connection is modified by introducing an additional beam phase coupled to the original beam linking F = 2 → F/ transition. The frequency of the additional beam is offset from that of the original beam by ≈ +10Γ (Γ is natural linewidth). Such a two-beam configuration in F→F/ manifold effectively satisfies conditions of Vee (V) linkage or degenerate two-level connection (DTLC), depending on the detuning of the 780nm laser. This transformation profoundly affects the behavior of the ensuing Ladder (Ξ) system. While the (I) Ξ +V condition is favorable for Electromagnetically Induced Transparency (EIT), the (ii) Ξ + DTLC brings in the effect of Electromagnetically Induced Absorption (EIA). The EIT-dominated situation is helpful for FWM to take place, and the EIA effect augments the stronger presence of DROP. This condition is verified by monitoring the blue fluorescence emanating from the 5D→6P3/2→5S1/2 decay route. The DROP effect follows the Amplified Spontaneous Emission (ASE) pattern in the media. The origin of blue photons is also due to FWM under EIT conditions. In the case of EIA, the dominant condition increment in blue fluorescence is due to increased stimulated emission. The blue photons mainly contributed by (i) FWM and (ii) increased participation of stimulated emission are directional in nature and phase coherent.

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Section: Resultsmentioning

confidence: 69%

Two-photon coherence in a DROP-FWM medium

Shukla,

Ray

2024

Phys. Scr.

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“…The RIR phenomenon was also employed to observe very high optical gain in anisotropic medium [13] as well as to observe collective effects as in the collective atomic recoil laser (CARL), which was firstly proposed theoretically in [14] and experimentally demonstrated in [15]. Using a four-wave mixing (FWM) configuration in a degenerate two-level system of cold cesium atoms, where Zeeman coherence as well as coherence between momentum states via RIR can be excited, our group has observed a giant optical gain and self-oscillation [16] through coupled cascading parametric backward-and forward-FWM (FFWM).…”

Section: Introductionmentioning

confidence: 99%

“…Indeed, differently from the memories based on ground state coherences associated with the Zeeman sub levels, we have demonstrated its non volatility and robustness to the reading process, which does not destroy the stored information, so its storage time is mainly determined by the atomic motion. Moreover, using the gain mechanism described in [16], we have also demonstrated the operation of an atomic memory that can amplify the stored signal during the reading process [19].…”

Section: Introductionmentioning

confidence: 99%

Atomic memory based on recoil-induced resonances

Capella¹,

Melo²,

Lopez³

et al. 2021

Preprint

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In this work we perform a detailed theoretical and experimental investigation of an atomic memory based on recoil-induced resonance in cold cesium atoms. We consider the interaction of a nearly degenerated pump and probe beams with an ensemble of two-level atoms. A full theoretical density matrix calculation in the extended Hilbert space of the internal and external atomic degrees of freedom allows us to obtain, from first principles, the transient and stationary responses determining the probe transmission and the forward four-wave mixing spectra. These two signals are generated together at the same order of perturbation with respect to the intensities of pump and probe beams. However, during continuous excitation of the sample, they are detected in very different ways and the signal at the probe transmission appears to be considerably larger, being the main focus of investigation prior to this work. Moreover, we have investigated the storage of optical information in the atomic external degrees of freedom, which provided a simple interpretation for the previously-reported non-volatile character of this memory. The retrieved signals after storage reveal the equivalent role of probe transmission and four-wave mixing, as the two signals have similar amplitudes. Probe transmission and forward four-wave-mixing spectra were then experimentally measured for both continuous excitation and after storage. The experimental observations are in good agreement with the developed theory and open a new pathway for the reversible exchange of optical information with atomic systems.

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