Interacting double dark resonances in a tripod system of room-temperature 4He
29 Dec 2010-Vol. 8173
TL;DR: In this article, two different tripod configurations using metastable 4 He, with the probe perpendicular and parallel to the quantization axis, defined by an applied weak magnetic field, were experimentally studied.
Abstract: We experimentally study two different tripod configurations using metastable 4 He, with the probe perpendicular and
parallel to the quantization axis, defined by an applied weak magnetic field. In the first case, the two dark resonances
interact incoherently and merge together into a single transparency peak with increasing coupling power. In the second
case, we observe destructively interfering double dark resonances leading to a narrow absorption dip at the line center.
We confirm the results theoretically.
Citations
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Proceedings Article•
12 May 2000TL;DR: In this article, a simple theoretical model for electromagnetically induced absorption (EIA) was proposed for a four-state N-atom system, where the EIT-resonance with negative sign was obtained only for three-state /spl Lambda/- and V-systems.
Abstract: Summary form only given. It is well-known that nonlinear interference effects in the resonant atom-light interaction can lead to interesting and important phenomena, such as electromagnetically induced transparency (EIT) of atomic medium, coherent population trapping, lasing without inversion, and others. Common to all these phenomena is the appearance of light-induced coherence between atomic levels, which are not coupled by dipole transitions. Recently Akulshin and co-workers (1998-9) have observed subnatural-width resonances in the absorption on the D/sub 2/ line of rubidium vapor under excitation by two copropagating optical waves with variable frequency offset. It is remarkable that, apart from expected EIT-resonances with negative sign, authors detected positive resonances termed as electromagnetically induced absorption (EIA). More recently, similar effects in a (3+5)-state system have been described as a result of constructive interference of the dipole excitation channels. We propose a simple theoretical model for EIA - a four-state N-atom. Remember that three-state /spl Lambda/- and V-systems give the EIT-resonances only.
148 citations
TL;DR: In this article, the EIT windows were obtained for purely electronic spins in the presence of Doppler broadening and the positive role of collisions was emphasized through measurements of the power dependence of EIT resonance.
Abstract: Electromagnetically induced transparency (EIT) is observed in gaseous 4He at room temperature. Ultra-narrow (less than 10 kHz) EIT windows are obtained for the first time for purely electronic spins in the presence of Doppler broadening. The positive role of collisions is emphasized through measurements of the power dependence of the EIT resonance. Measurement of slow light opens up possible ways to applications.
28 citations
Posted Content•
TL;DR: In this article, a model for the numerical calculation of the response of a degenerate two-level system to the action of an arbitrarily intense resonant pump field and a weak probe in the presence of a magnetic field is presented.
Abstract: Spectroscopic features revealing the coherent interaction of a degenerate two-level atomic system with two optical fields are examined. A model for the numerical calculation of the response of a degenerate two-level system to the action of an arbitrarily intense resonant pump field and a weak probe in the presence of a magnetic field is presented. The model is valid for arbitrary values of the total angular momentum of the lower and upper levels and for any choice of the polarizations of the optical waves. Closed and open degenerate two-level systems are considered. Predictions for probe absorption and dispersion, field generation by four-wave-mixing, population modulation and Zeeman optical pumping are derived. On all these observables, sub-natural-width coherence resonances are predicted and their spectroscopic features are discussed. Experimental spectra for probe absorption and excited state population modulation in the D2 line of Rb vapor are presented in good agreement with the calculations
1 citations
References
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TL;DR: In this article, the authors predict the possibility of sharp, high contrast resonances in the optical response of a broad class of systems, wherein interference effects are generated by coherent perturbation or interaction of dark states.
Abstract: We predict the possibility of sharp, high-contrast resonances in the optical response of a broad class of systems, wherein interference effects are generated by coherent perturbation or interaction of dark states. The properties of these resonances can be manipulated to design a desired atomic response.
279 citations
TL;DR: Compared with that generated in a single-dark-resonance system, the Kerr nonlinearity can be enhanced by several orders of magnitude with vanishing linear absorption.
Abstract: A scheme for giant enhancement of the Kerr nonlinearity in a four-level system with double dark resonances is proposed. Compared with that generated in a single-dark-resonance system, the Kerr nonlinearity can be enhanced by several orders of magnitude with vanishing linear absorption. We attribute this dramatic enhancement to the interaction of dark resonances.
161 citations
TL;DR: In this paper, the interaction of a weak probe field, having two orthogonally polarized components, with an optically dense medium of four-level atoms in a tripod configuration was studied.
Abstract: We study the interaction of a weak probe field, having two orthogonally polarized components, with an optically dense medium of four-level atoms in a tripod configuration. In the presence of a coherent driving laser, electromagnetically induced transparency is attained in the medium, dramatically enhancing its linear as well as nonlinear dispersion while simultaneously suppressing the probe field absorption. We present the semiclassical and fully quantum analysis of the system. We propose an experimentally feasible setup that can induce large Faraday rotation of the probe field polarization and therefore be used for ultrasensitive optical magnetometry. We then study the Kerr nonlinear coupling between the two components of the probe, demonstrating a novel regime of symmetric, extremely efficient cross-phase modulation, capable of fully entangling two single-photon pulses. This scheme may thus pave the way to photon-based quantum information applications, such as deterministic all-optical quantum computation, dense coding, and teleportation.
157 citations
Additional excerpts
...We obtain an expression for the probe susceptibility as ) = ΓR) + ΓR) 2 δ+Δc 3 ΓR + ΓR Ωc 2 2 δ ΓR) , (10)...
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TL;DR: A simple theoretical model describing the positive sign of subnatural-width absorption resonances in the recent experiment of Akulshin and co-workers is proposed in this paper, where an analytical expression for the linear response to the weak probe field is found in the low-saturation limit with respect to the control field.
Abstract: A simple theoretical model describing the positive sign of subnatural-width absorption resonances in the recent experiment of Akulshin and co-workers [Phys. Rev. A 57, 2996 (1998)] is proposed. An analytical expression for the linear response to the weak probe field is found in the low-saturation limit with respect to the control field. It is shown that the positive sign of subnatural resonance is caused by the spontaneous transfer of the light-induced coherence from the excited level to the ground one.
155 citations