Coherent interaction of laser pulses in a resonant optically dense extended medium under the regime of strong field-matter coupling

Abstract

Nonstationary pump-probe interaction between short laser pulses propagating in a resonant optically dense coherent medium is considered. A special attention is paid to the case, where the density of two-level particles is high enough that a considerable part of the energy of relatively weak external laser-fields can be coherently absorbed and reemitted by the medium. Thus, the field of medium reaction plays a key role in the interaction processes, which leads to the collective behavior of an atomic ensemble in the strongly coupled light-matter system. Such behavior results in the fast excitation interchanges between the field and a medium in the form of the optical ringing, which is analogous to polariton beating in the solid-state optics. This collective oscillating response, which can be treated as successive beats between light wave-packets of different group velocities, is shown to significantly affect propagation and amplification of the probe field under its nonlinear interaction with a nearly copropagating pump pulse. Depending on the probe-pump time delay, the probe transmission spectra show the appearance of either specific doublet or coherent dip. The widths of these features are determined by the density-dependent field-matter coupling coefficient and increase during the propagation. Besides that, the widths of the coherent features, which appear close to the resonance in the broadband probe-spectrum, exceed the absorption-line width, since, under the strong-coupling regime, the frequency of the optical ringing exceeds the rate of incoherent relaxation. Contrary to the stationary strong-field effects, the density-and coordinate-dependent transmission spectra of the probe manifest the importance of the collective oscillations and cannot be obtained in the framework of the single-atom model.

Propagation of two short laser pulse trains in a Λ-type three-level medium under conditions of electromagnetically induced transparency

“…4. Clearly, we see some differences between the two cases, especially in the trailing edge of the probe pulse, where the optical ringing [23,24] occur for both cases, however the oscillations in the trailing edge disappear for symmetric detunings case for larger t/T because a steady dark state is reached quite fast after the interaction with the first 20 pulses for optical depths µ p ζ < 6 ps −1 . As mentioned before, these differences come from the contribution of all other off-resonant comb modes of both lasers, Fig.…”

Quantum optics of ultracold quantum gases: open systems beyond dissipation (habilitation thesis)

“…(1.48) gives a two-satellite contour (1.51) reflecting normalmode splitting of two oscillators ⟨𝑎 0,1 ⟩ coupled through atoms. Here, two strongly coupled oscillators are the two light modes, which is different from the usual cavity QED normal-mode splitting (vacuum Rabi splitting), where the two coupled oscillators are light and near-resonant atoms [101][102][103][104][105][106][107][108][109][110]. This was observed [111] for collective strong coupling, i.e., the splitting 𝑈 10 ⟨ D10 ⟩ exceeding 𝜅.…”

Взаимодействие Модулированных По Фазе Фемтосекундных Импульсов С Оптически Плотной Квазирезонансной Средой Паров Рубидия

“…Было показано, что этот эффект связан с возбуждением резонансной поляризации в виде неадиабатического квантового скачка, а излучение среды представляет собой индуцированное суперизлучение протяженной плотной резонансой среды без инверсии заселенностей. Аналогичный эффект наблюдается как в лазерах с внутрирезонаторной поглощающей ячейкой в режиме синхронизации мод [9], так и в свободном пространстве [10,11].…”