Summary form only given. The phenomenon of electromagnetically induced transparency (EIT) has been the subject of extensive experimental and theoretical studies in recent years, since it has a fundamental significance and a host of important applications. To produce EIT one requires a strong laser field, which often undergoes random fluctuations. The case of amplitude-phase fluctuations appears to be much more complicated and richer than the case of Markovian phase fluctuations. Here we consider transparency induced by a Gaussian-Markovian amplitude-phase fluctuating (chaotic) field. The problem involves five parameters: the coupling field rms Rabi frequency, bandwidth, detuning, and the widths of the material and coupled transitions.
Summary form only given. The phenomenon of electromagnetically induced transparency (EIT) has been the subject of extensive experimental and theoretical studies in recent years, since it has a fundamental significance and a host of important applications. To produce EIT one requires a strong laser field, which often undergoes random fluctuations. The case of amplitude-phase fluctuations appears to be much more complicated and richer than the case of Markovian phase fluctuations. Here we consider transparency induced by a Gaussian-Markovian amplitude-phase fluctuating (chaotic) field. The problem involves five parameters: the coupling field rms Rabi frequency, bandwidth, detuning, and the widths of the material and coupled transitions.
This paper deals with electromagnetically induced transparency (EIT), i.e., a significant suppression of absorption at a material transition (in the form of a dip in an absorption spectrum), due to a strong laser field, coupling the excited level with an auxiliary excited (unpopulated) level. A comprehensive theory of EIT is developed for the cases of coherent and Markovian phase- and amplitude-phase-fluctuating coupling fields. For a coherent coupling field, a shift of the absorption minimum from the two-photon resonance is revealed in the off-resonance case. Two models of amplitude-phase fluctuating fields are considered: the chaotic field and the uncorrelated-jump field. Closed analytical expressions for EIT line shape are derived and exact limits of different regimes of EIT are obtained, the emphasis being on the near-resonance case. The main conclusion is that an amplitude-phase-fluctuating field can induce significant transparency, though reduced in comparison to a phase-fluctuating field of the same average intensity and bandwidth. EIT decreases with the increase of the bandwidth for all stochastic models considered. EIT with a chaotic field is generally less pronounced than EIT with an uncorrelated-jump field of the same intensity and bandwidth, the difference increasing with the field intensity. The possibility of experimental verification of the results obtained is discussed.
Electromagnetically induced transparency (EIT) with chaotic field is considered for the constructive-interference case ( i.e. ,when the material transition is much narrower than the coupled one). The field intensity fluctuations are shown to induce a narrow peak at the material frequency, in addition to the familiar Autler-Towns doublet. The dependence of the fluctuation-induced peak on the field bandwidth ν is obtained analytically and numerically. EIT is shown to increase with ν for sufficiently small ν.
The present paper treats the electromagnetically induced transparency (EIT), i.e., the absorption spectrum of a weak probe field, near-resonant to a material transition, in the presence of a strong amplitude-phase fluctuating field which couples the upper level of the transition to another excited level. The coupling field is assumed to be chaotic (i.e., a complex Gaussian process with a Lorentzian spectrum) and so strong that the material relaxation and the detuning can be neglected. In addition, we consider the Fourier transform of the spectrum Uaa(t), which determines absorption of a probe field with a time-dependent intensity. The quantity Uaa(t) equals a diagonal element of the average reduced evolution operator of the two-level system (TLS), coupled by the strong field. As a starting point, we use the stationary, partially averaged stochastic Schr\"odinger equation, which has the form of a set of two second-order differential equations. The theory is developed by combining analytical and numerical approaches. For the most important regime, when the rms Rabi frequency V0 is much greater than the coupling-field bandwidth $\ensuremath{\nu},$ we obtain scaling relations for the EIT line shape and the TLS evolution. In particular, the absorption at the minimum (i.e., at the resonance frequency) scales as ${\ensuremath{\nu}}^{1/3}{V}_{0}^{\ensuremath{-}4/3},$ whereas the evolution function Uaa(t) performs damped oscillations with the decay rate on the order of ${(V}_{0}^{2}\ensuremath{\nu}{)}^{1/3}.$ These results differ significantly from those following from the uncorrelated-jump model. The results of this paper are shown to be applicable to more general models of amplitude-phase fluctuations than the Gaussian-Markovian chaotic field.
Summary form only given. It is well known that strong resonant laser radiation can significantly modify absorption and emission spectra of matter, producing such features, as the Autler-Towns doublet, the dark resonance, etc. Laser fluctuations, which are often inevitable, usually tend to smear out the field-induced spectral features. Here, however, we show that in an experimental scheme, usually used to obtain electromagnetically induced transparency (EIT), intensity fluctuations of a strong coupling field can induce a narrow peak in the probe absorption spectrum.
Strong evidence indicating the occurrence of electromagnetically induced transparency (EIT) in a solid medium was found. Fluorescence reduction due to EIT was observed in solids. The excitation intensity dependence of the fluorescence reduction was found to be consistent with theoretical predictions for EIT. It was experimentally demonstrated that the essential condition for the observation of EIT in solids is that the Rabi frequency of excitation must be larger than the inhomogeneous width of the transition between the two states coupled to the third state by the pair of optical fields.
Abstract Electromagnetically induced transparency (EIT) stems from a quantum system, where an opaque atomic medium appears the narrow transparent state within a wide absorption area. This phenomenon can be achieved by quantum interference of pumping light and detecting light at different energy levels of transitions. In the generation process of EIT effect, in addition to transparent state, the atomic medium is usually accompanied with a strong dispersion effect, which will bright about a significant reduction of light velocity, thus realizing many important applications, such as slow light propagations. Although the EIT effect has many important applications, its application scenarios are greatly limited due to the fact that EIT realization usually requires specific and complicated conditions, such as refrigeration temperature, high intensity laser, etc. Recently, the analogue of EIT effect in metamaterial has attracted increasing attentions due to its advantages such as controllable room temperature and large operating bandwidth. Metamaterial analogue of EIT effect has become a new research focus. In this article, we review current research progresses on EIT metamaterials. Firstly, we describe the theoretical models for analyzing EIT metamaterials, including the mechanical oscillator model and the equivalent circuit model. Then, we describe the simulations, designs and experiments of passive EIT metamaterials with fixed structures and active EIT metamaterials with tunable elements. Furthermore, the applications of EIT metamaterials in the areas of slow lights, sensings, absorptions and other fields are also reviewed. Finally, the possible directions and key issues of future EIT metamaterial researches are prospected.