Superluminal optical pulse propagation in nonlinear coherent media
- Department of Theoretical Physics, Yerevan Physics Institute, Alikhanian Brothers 2, 375036 Yerevan, (Armenia)
- Institute for Physics Research, Armenian National Academy of Sciences, Ashtarak-2, 378410, (Armenia)
We investigate a light-pulse propagation with negative group velocity in a nonlinear coherent medium. We show that the necessary conditions for nonlinear superluminal effects to be observable are realized in a three-level {lambda} system interacting with a linearly polarized laser field in the presence of a static magnetic field. The initially prepared Zeeman coherence cancels the resonant absorption of the medium almost completely, but preserves its dispersion anomalous and very high. In this medium the light pulse propagates superluminally in the sense that the peak of the transmitted pulse exits the medium before the peak of the incident pulse enters. At the same time the pulse group velocity is intensity dependent, which leads to the self-steepening of the pulse trailing edge due to the fact that the more intense parts of the pulse travel slower. This is in contrast with the shock wave generation in a nonlinear medium with normal dispersion. The predicted effect can be easily observed in the well-known schemes employed in the studies of nonlinear magneto-optical rotation. The upper bound of sample length is found from the criterion that the pulse self-steepening and group-advance time are observable without pulse distortion caused by the group-velocity dispersion.
- OSTI ID:
- 20639814
- Journal Information:
- Physical Review. A, Vol. 67, Issue 6; Other Information: DOI: 10.1103/PhysRevA.67.063806; (c) 2003 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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