From fast to slow light in a resonantly driven absorbing medium

Macke, Bruno; Segard, Bernard

Document type :

Compte-rendu et recension critique d'ouvrage

DOI :

10.1103/PhysRevA.82.023816

Title :

From fast to slow light in a resonantly driven absorbing medium

Author(s) :

Macke, Bruno [Auteur]

Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 [PhLAM]
Segard, Bernard [Auteur]

Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 [PhLAM]

Journal title :

Physical Review A : Atomic, molecular, and optical physics [1990-2015]

Pages :

023816

Publisher :

American Physical Society

Publication date :

2010-08-23

ISSN :

1050-2947

HAL domain(s) :

Physique [physics]/Physique [physics]/Optique [physics.optics]

English abstract : [en]

We theoretically study the propagation through a resonant absorbing medium of a time-dependent perturbation modulating the amplitude of a continuous wave (cw). Modeling the medium as a system of two-level atoms and linearizing ...
Show more >We theoretically study the propagation through a resonant absorbing medium of a time-dependent perturbation modulating the amplitude of a continuous wave (cw). Modeling the medium as a system of two-level atoms and linearizing the Maxwell-Bloch equations for the perturbation, we establish an exact analytical expression of the transfer function relating the Fourier transforms of the incident and transmitted perturbations. It directly gives the gain and the phase shift undergone in the medium by a harmonic modulation. For the case of a pulse modulation, it enables us to determine the transmission time of the pulse center-of-mass (group delay), evidencing the relative contributions of the coherent and incoherent (population) relaxation. We show that the group delay has a negative value (fast light) fixed by the coherent effects when the cw intensity is small compared to the saturation intensity and becomes positive (slow light) when this intensity increases, before attaining a maximum that cannot exceed the population relaxation time. The analytical results are completed by numerical determinations of the shape of the transmitted pulses in the different regimes.Show less >

Language :

Anglais

Popular science :

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