Subnatural linewidth in a strongly-driven degenerate two-level system

Chanu, Sapam Ranjita; Singh, Alok; Brun, Boris; Pandey, Kanhaiya; Natarajan, Vasant

doi:10.1016/j.optcom.2011.07.001

Cited by 16 publications

(11 citation statements)

References 16 publications

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“…7(b). In a recent study [30], we have shown that EIA can also be observed in a degenerate two-level transition with just one control laser. There again, the transition was from F to F + 1, so that the larger number of magnetic sublevels in the upper level allowed the formation of an N -type system.…”

mentioning

confidence: 80%

Conversion between electromagnetically induced transparency and absorption in a three-level lambda system

Chanu¹,

Pandey²,

Natarajan³

2012

EPL

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We show that it is possible to change from a subnatural electromagnetically induced transparency (EIT) feature to a subnatural electromagnetically induced absorption (EIA) feature in a (degenerate) three-level Λ system. The change is effected by turning on a second control beam counter-propagating with respect to the first beam. We observe this change in the D2 line of Rb in a room temperature vapor cell. The observations are supported by density-matrix analysis of the complete sublevel structure including the effect of Doppler averaging, but can be understood qualitatively as arising due to the formation of N -type systems with the two control beams. Since many of the applications of EIT and EIA rely on the anomalous dispersion near the resonances, this introduces a new ability to control the sign of the dispersion.

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confidence: 80%

Conversion between electromagnetically induced transparency and absorption in a three-level lambda system

Chanu¹,

Pandey²,

Natarajan³

2012

EPL

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“…The rotation is induced by a strong co-propagating circularly polarized control laser driving the same transition, similar to the phenomenon of electromagnetically induced transparency (EIT) [12] and electromagnetically induced absorption (EIA) [13]. In both cases, the control laser modifies the susceptibility of the medium.…”

Section: Introductionmentioning

confidence: 93%

Polarization-rotation resonances with subnatural widths using a control laser

Chanu¹,

Pandey²,

Bharti³

et al. 2014

EPL

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We demonstrate extremely narrow resonances for polarization rotation in an atomic vapor. The resonances are created using a strong control laser on the same transition, which polarizes the atoms due to optical pumping among the magnetic sublevels. As the power in the control laser is increased, successively higher-order nested polarization rotation resonances are created, with progressively narrower linewidths. We study these resonances in the D2 line of Rb in a room temperature vapor cell, and demonstrate a width of 0.14 Γ for the third-order rotation. The physical basis for the observed resonances is that optical pumping results in a simplified ΛV-type level structure with differential dressing of the levels by the control laser, which is why the control power has to be sufficiently high for each resonance to appear. This explanation is borne out by a density-matrix analysis of the system. The dispersive lineshape and subnatural width of the resonance lends itself naturally to applications such as laser locking to atomic transitions and precision measurements.

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“…In 1992, Allen et al showed that LG laser mode has a well-defined OAM, as lh per photon, and proposed an experiment to observe the torque on cylindrical lenses arising from the reversal of the helicity of a LG mode [9]. An additional motivation for recent studies of LG beams is as a route to obtaining narrower the electromagnetically induced transparency (EIT) spectrum than the conventional Gaussian one [10][11][12]. The transmission of structured light has been measured using the phase profile in cold rubidium atoms and been shown that the EIT is spatially dependent for vortex light beams [13].…”

Section: Introductionmentioning

confidence: 99%

Spatially dependent atom-photon entanglement

Sabegh¹,

Amiri²,

Mahmoudi³

2018

Preprint

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The atom-photon entanglement using the Laguerre-Gaussian beams is studied in the closedloop three-level V -type quantum systems. We consider two schemes with degenerated and nondegenerated upper levels: in the first, the effect of the quantum interference due to the spontaneous emission is taken into account and in the second, a microwave plane wave is applied to the upper levels transition for non-degenerated scheme. It is shown that the atom-photon entanglement in both schemes depends on the intensity profile as well as the orbital angular momentum (OAM) of applied fields so that the various spatially dependent entanglement patterns can be generated by Laguerre-Gaussian beams with different OAMs. However, no entanglement appears in the center of optical vortex beams, because of the zero intensity. As a result, the entanglement between atoms and its spontaneous emissions in different points of the atomic cell can be controlled by the OAM of the applied fields. Moreover, our numerical results show that the number of the local maximum degree of entanglement peaks are determined by the OAM of the applied fields. It seems that the present results would greatly facilitate the determination of the OAM and may find the broad applications in quantum information processing.

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Subnatural linewidth in a strongly-driven degenerate two-level system

Cited by 16 publications

References 16 publications

Conversion between electromagnetically induced transparency and absorption in a three-level lambda system

Conversion between electromagnetically induced transparency and absorption in a three-level lambda system

Polarization-rotation resonances with subnatural widths using a control laser

Spatially dependent atom-photon entanglement

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