Theory of thermal motion in electromagnetically induced transparency: Effects of diffusion, Doppler broadening, and Dicke and Ramsey narrowing

Firstenberg, Ofer; Shuker, Moshe; Pugatch, Rami; Fredkin, D. R.; Davidson, Nir; Ron, A.

doi:10.1103/physreva.77.043830

Cited by 57 publications

(61 citation statements)

References 41 publications

(82 reference statements)

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“…The exceptions to this principle are atom-atom and atomwall collisions, field inhomogeneity, Doppler broadening, and other velocity effects [44]. In -GEM memories the field is homogeneous on the plane transverse to the solenoid axis.…”

Section: B Diffusion Of Tem 00mentioning

confidence: 99%

Spatial-mode storage in a gradient-echo memory

et al. 2012

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Three-level atomic gradient echo memory ( -GEM) is a proposed candidate for efficient quantum storage and for linear optical quantum computation with time-bin multiplexing [Hosseini et al., Nature (London) 461, 241 (2009)]. In this paper we investigate the spatial multimode properties of a -GEM system. Using a high-speed triggered CCD, we demonstrate the storage of complex spatial modes and images. We also present an in-principle demonstration of spatial multiplexing by showing selective recall of spatial elements of a stored spin wave. Using our measurements, we consider the effect of diffusion within the atomic vapor and investigate its role in spatial decoherence. Our measurements allow us to quantify the spatial distortion due to both diffusion and inhomogeneous control field scattering and compare these to theoretical models.

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Section: B Diffusion Of Tem 00mentioning

confidence: 99%

Spatial-mode storage in a gradient-echo memory

et al. 2012

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“…Physical processes leading to line narrowing or broadening of coherent resonances were extensively studied under different experimental conditions, laser beam geometries, and cell dimensions [7][8][9][10][11][12]16,[25][26][27][28]. Figures 12(a) and 12(b) show experimental and theoretical results for the dependence Fig.…”

Section: Theoretical Modelmentioning

confidence: 97%

“…The latter will be referred to throughout this paper as the laser beam. For the interaction of the Gaussian or laser beam with alkali-metal-atom vapor, the different effects such as Ramsey and Dicke narrowing, transit time, and Doppler broadening are examined either in vacuum [7,8] or in buffer gas cells [9][10][11][12] The differences in EIT line shapes for Gaussian and laser beams were presented in [13][14][15] by considering only the entire laser beam contribution without focusing on the details of laser-atom interaction within the laser beam. However, different parts of the laser beam cross section, after passing through the alkali-metal vapor cell, carry different information about the atomic state and yield different EIT resonances [16].…”

Section: Introductionmentioning

confidence: 99%

Evolution of dark state of an open atomic system in constant intensity laser field

et al. 2011

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We studied experimentally and theoretically the evolution of open atomic systems in the constant intensity laser field. The study is performed by analyzing the line shapes of Hanle electromagnetically induced transparency (EIT) obtained in different segments of a laser beam cross section of constant intensity, i.e., a -shaped laser beam. Such Hanle EIT resonances were measured using a small movable aperture placed just in front of the photodetector, i.e., after the entire laser beam had passed through the vacuum Rb cell. The laser was locked to the open transition F g = 2 → F e = 1 at the D 1 line of 87 Rb with laser intensities between 0.5 and 4 mW/cm 2 . This study shows that the profile of the laser beam determines the processes governing the development of atomic states during the interaction. The resonances obtained near the beam center are narrower than those obtained near the beam edge, but the significant changes of the linewidths occur only near the beam edge, i.e., right after the atom enters the beam. The Hanle EIT resonances obtained near the beam center exhibit two pronounced minima next to the central maximum. The theoretical model reveals that the occurrence of these transmission minima is a joint effect of the preparation of atoms into the dark state and the optical pumping into the uncoupled ground level F g = 1. The appearance of the transmission minima, although similar to that observed in the wings of a Gaussian beam [A. J. Krmpot et al., Opt. Express 17, 22491 (2009)], is of an entirely different nature for the -shaped laser beam.

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“…Here, we show that by carefully tuning the light-matter interaction, the optical diffraction of such images can be eliminated completely [2]. We utilize Dicke narrowing in a room-temperature EIT medium with buffer gas to obtain a susceptibility that is quadratic in the transverse momentum space [3]. By setting a negative Raman-detuning and carefully tuning the EIT parameters, the refraction induced by the atomic motion completely counterbalances the paraxial optical diffraction of the probe and by that eliminates the effect of diffraction.…”

mentioning

confidence: 99%

Diffraction elimination of slow images

Firstenberg

Shuker

Ron

et al. 2009

CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference

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All classical wave fields are subjected to diffraction throughout their propagation. In many systems, a reduction or elimination of the diffraction spreading of beamlike fields are obtained by manipulating the susceptibility in real space and inducing a gradient of the index of refraction. Similarly to wave-guiding, only specific modes may propagate in the induced wave-guides without diffraction or, equivalently, images are revived after a certain selfimaging distance. However in these schemes, diffraction is not suppressed for an arbitrary image and for any distance along the propagation direction.It was recently demonstrated that images, imprinted on a 'probe' laser pulses, may be dramatically slowed when traversing a vapor medium of electromagnetically induced transparency (EIT) [1]. Here, we show that by carefully tuning the light-matter interaction, the optical diffraction of such images can be eliminated completely [2]. We utilize Dicke narrowing in a room-temperature EIT medium with buffer gas to obtain a susceptibility that is quadratic in the transverse momentum space [3]. By setting a negative Raman-detuning and carefully tuning the EIT parameters, the refraction induced by the atomic motion completely counterbalances the paraxial optical diffraction of the probe and by that eliminates the effect of diffraction. Somewhat surprisingly, the diffusion, which regularly occurs for slow light in thermal vapor, can also be canceled in this regime. The unavoidable absorption that accompanies the process is independent of the transverse momentum and can therefore be compensated for by any uniform gain mechanism.In effect, the random thermal motion of the atoms is exploited to trap the light in the plane perpendicular to the propagation direction. In an analogy to the Doppler trapping of atoms, due to the negative detuning, outwards-confronting light components couple more efficiently to inwards moving atoms, counterbalancing the natural diffraction of the light [ Fig. 1(a)]. This results in a 'Doppler trapping' of light by atoms in two dimensions. Indeed, a unique manifestation of the scheme is the ability to suspend the expansion of narrow beams regardless of their position [ Fig. 1(b)]. Fig. 1 (a) Pump-Probe geometry and an illustration of the Doppler trapping of light: EIT in the medium depends on the transverse wave-vector k⊥, such that any k⊥-component is coupled more efficiently to the atoms that move in the opposite direction and is effectively 'dragged' back inwards. (b) An incident beam of two Gaussians (dashed black) propagating one Rayleigh length (∆ is the Raman detuning, Γ is the EIT width, and k0=(Γ/D) 1/2 , where D is the diffusion coefficient). The normalized transmitted images and cross-sections (blue) are shown for: free-space diffraction (left), on-resonance EIT (center), and negative detuning (right), exhibiting no diffraction and no diffusion No other vapor medium exists that eliminates the optical diffraction of arbitrary images all throughout their propagation. Applications of this scheme ...

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Theory of thermal motion in electromagnetically induced transparency: Effects of diffusion, Doppler broadening, and Dicke and Ramsey narrowing

Cited by 57 publications

References 41 publications

Spatial-mode storage in a gradient-echo memory

Spatial-mode storage in a gradient-echo memory

Evolution of dark state of an open atomic system in constant intensity laser field

Diffraction elimination of slow images

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