Experimental investigation of the transition between Autler-Townes splitting and electromagnetically-induced-transparency models

Abstract

Two phenomena can affect the transmission of a weak signal field through an absorbing medium in the presence of a strong additional field: electromagnetically induced transparency (EIT) and Autler-Townes splitting (ATS). Being able to discriminate between the two is important for various applications. Here we present an experimental investigation into a method that allows for such a disambiguation as proposed in [Phys. Rev. Lett. 107, 163604 (2011)]. We apply the proposed test based on Akaike's information criterion to a coherently driven ensemble of cold cesium atoms and find a good agreement with theoretical predictions, therefore demonstrating the suitability of the method. Additionally, our results demonstrate that the value of the Rabi frequency for the ATS/EIT model transition in such a system depends on the level structure and on the residual inhomogeneous broadening.PACS numbers: 42.50. Gy, 42.50.Ct, Fine engineering of interactions between light and matter is critical for various purposes, including information processing and high-precision metrology. For more than two decades, coherent effects leading to quantum interference in the amplitudes of optical transitions have been widely studied in atomic media, opening the way to controlled modifications of their optical properties [1]. More specifically, such processes as coherent population trapping [2,3] or electromagnetically induced transparency (EIT) [4-6] allow one to take advantage of the modification of an atomic system by a so-called control field to change the transmission characteristics of a probe field. These features are especially important for the implementation of optical quantum memories [7] relying on dynamic EIT [8], or for coherent driving of a great variety of systems, ranging from superconducting circuits [9] to nanoscale optomechanics [10].However, if in general the transparency of an initially absorbing medium for a probe field is increased by the presence of a control field, two very different processes can be invoked to explain it in a Λ-type configuation. One of them is a quantum Fano interference between two paths in a three-level system [11], which occurs even at very low control intensity and gives rise to EIT [12]. The other one is the appearance of two dressed states in the excited level at large control intensity, corresponding to the Autler-Townes splitting (ATS) [13][14][15]. Discerning whether a transparency feature observed in an absorption profile is the signature of EIT or ATS is therefore crucial [16][17][18]. A recent paper by P.M. Anisimov, J.P. Dowling and B.C. Sanders [19] introduced a versatile and quantitative test to discriminate between these two phenomena.In this paper, we report an experimental study of the proposed witness, relying on a detailed analysis of the absorption profile of a probe field in an atomic ensemble in the presence of a control field. In order to analyze the quantum interferences in detail and avoid any inhomogeneous broadening, our study is performed with an ensemble of cold cesium ato...

What is and what is not electromagnetically induced transparency in whispering-gallery microcavities

“…They have successfully applied this test to an experiment with a one-dimensional (1D) superconducting transmission line coupled to a flux qubit, concluding that the reported data 16 do not support the claim of EIT. In a recent study, Giner et al 49 demonstrated the suitability of the AIC criterion to evaluate EIT and ATS in experiments with cold caesium atoms. Oishi et al 50 suggested that the transient response of a system can be used to discern EIT from ATS.…”

Discerning quantum memories based on electromagnetically-induced-transparency and Autler-Townes-splitting protocols

“…Our investigation adds a fresh applications-based perspective to the ongoing discussion centered on phenomenon-based comparisons between EIT and ATS [4,5,[7][8][9][10][11]. Further, it clarifies any potential confusion that may arise between the two perceivably similar EIT and ATS memory protocols, which is important because by understanding the underlying mechanisms of these memories, a proper approach to optimization can be taken: one that yields the best results for a given set of technical and design limitations.…”

“…This common feature has been at the centre of a longstanding confusion as to whether an observed transparency is due to EIT or ATS, and as such, the distinction between the two is an active topic of research in the quantum optics community. Recently, it has been shown theoretically [4][5][6] as well as experimentally [7][8][9][10][11] that it is possible to objectively distinguish the regime where EIT dominates (EIT regime) from the one where ATS dominates (ATS regime).…”

Electromagnetically induced transparency and Autler-Townes effect in a generalized L-system: A five-level model

“…The two phenomena coexist and the contribution from the EIT prevails over that originating from the A-T effect at low coupling Rabi frequencies, up to their values approximately equal to the natural linewidth. On the other hand, the A-T effect starts to dominate at the Rabi frequencies higher than these values [8][9][10][11].…”

“…A broad absorption minimum (a transparency window) is observed in the theoretical spectrum approximately at Δ p = 63 MHz. In connection with relatively high coupling Rabi frequency ( 51  5 tot ), one can expect that the transparency window in this work is mostly due to the A-T splitting and, to somewhat less extent, due to the EIT (see remarks in the Introduction, and references [8][9][10][11]). The very presence and the approximate position of this absorption minimum could be supposed by taking an analogy with a hypothetical three-level Λ scheme, where the state |5> plays a role of the (only) upper state.…”