Simultaneous slow and fast light involving the Faraday effect
Résumé
We theoretically study the linear transmission of linearly polarized
light pulses in an ensemble of cold atoms submitted to a static magnetic
field parallel to the direction of propagation. The carrier frequency
of the incident pulses coincides with a resonance frequency of the
atoms. The transmitted light, the electric field of which is transversal,
is examined in the polarizations parallel and perpendicular to that
of the incident pulses. We give explicit analytic expressions for the
transfer functions of the system for both polarizations and for the
corresponding group delays. We demonstrate that slow light can be
observed in a polarization, whereas fast light is simultaneously observed
in the perpendicular polarization. Moreover, we point out that, due
to the polarization post selection, the system is not necessarily
minimum phase shift. Slow light can then be obtained in situations
where an irrelevant application of the Kramers-Kronig relations could lead one
to expect fast light. When the incident light is step modulated, we
finally show that, in suitable conditions, the system enables one
to separate optical precursor and main field.
Domaines
Optique [physics.optics]
Origine : Fichiers produits par l'(les) auteur(s)
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