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Chinese Physics Letters

Raman Scattering in Coherently Prepared Atomic System

Lin Fu-Cheng, Jongmin Lee, Yongjoo Rhee, Jonghoon Yi, Hyunmin Park

Published Oct 10, 2001• 1 citation
Publisher

Abstract

Atoms in the coherent superposition state prepared by a pulse pair are used as a novel optical memory material where a single interrogation pulse will produce a new pulse pair preserving the relative amplitudes and phases of the preparing pulse pair. Such a coherent superposition state can also be specially tailored along the propagation path to generate Raman scattering in a relatively short distance with very high efficiency.

DOI
10.1088/0256-307x/18/11/315

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Atoms in the coherent superposition state prepared by a pulse pair are used as a novel optical memory material where a single interrogation pulse will produce a new pulse pair preserving the relative amplitudes and phases of the preparing pulse pair. Such a coherent superposition state can also be specially tailored along the propagation path to generate Raman scattering in a relatively short distance with very high efficiency.
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We consider the simultaneous propagation of a pair of Raman-resonant, frequency-modulated (chirped) laser pulses in an optically thick medium, modeled by an ensemble of $\ensuremath{\Lambda}$ atoms. A self-organization (``matching'') effect is shown for the chirped-pulse pair, which leads to a quasilossless propagation. Furthermore, we demonstrate that a well-defined coherent superposition of the atomic ground states and, correspondingly, a coherence are robustly created in the medium that can be controlled by amplitudes of the laser pulses. The proposed scheme can be applied to substantially increase the efficiency of the optical wave mixing processes, as well as in other nonlinear processes where the initial preparation of a spatially extended medium in a coherent superposition state is required.