dorsal/arxiv
View SchemaSuperluminal optical pulse propagation in nonlinear coherent media
| Authors | R. G. Ghulghazaryan, Yu. P. Malakyan |
|---|---|
| Categories | |
| ArXiv ID | physics/0209036 |
| URL | https://arxiv.org/abs/physics/0209036 |
| DOI | 10.1103/PhysRevA.67.063806 |
Abstract
The propagation of light-pulse with negative group-velocity in a nonlinear medium is studied theoretically. We show that the necessary conditions for these effects to be observable are realized in a three-level $\Lambda$-system interacting with a linearly polarized laser beam in the presence of a static magnetic field. In low power regime, when all other nonlinear processes are negligible, the light-induced Zeeman coherence cancels the resonant absorption of the medium almost completely, but preserves the dispersion anomalous and very high. As a result, a superluminal light pulse propagation can be observed in the sense that the peak of the transmitted pulse exits the medium before the peak of the incident pulse enters. There is no violation of causality and energy conservation. Moreover, the superluminal effects are prominently manifested in the reshaping of pulse, which is caused by the intensity-dependent pulse velocity. Unlike the shock wave formation in a nonlinear medium with normal dispersion, here, the self-steepening of the pulse trailing edge takes place due to the fact that the more intense parts of the pulse travel slower. The predicted effect can be easily observed in the well known schemes employed for studying 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.
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"abstract": "The propagation of light-pulse with negative group-velocity in a nonlinear\nmedium is studied theoretically. We show that the necessary conditions for\nthese effects to be observable are realized in a three-level $\\Lambda$-system\ninteracting with a linearly polarized laser beam in the presence of a static\nmagnetic field. In low power regime, when all other nonlinear processes are\nnegligible, the light-induced Zeeman coherence cancels the resonant absorption\nof the medium almost completely, but preserves the dispersion anomalous and\nvery high. As a result, a superluminal light pulse propagation can be observed\nin the sense that the peak of the transmitted pulse exits the medium before the\npeak of the incident pulse enters. There is no violation of causality and\nenergy conservation. Moreover, the superluminal effects are prominently\nmanifested in the reshaping of pulse, which is caused by the\nintensity-dependent pulse velocity. Unlike the shock wave formation in a\nnonlinear medium with normal dispersion, here, the self-steepening of the pulse\ntrailing edge takes place due to the fact that the more intense parts of the\npulse travel slower. The predicted effect can be easily observed in the well\nknown schemes employed for studying of nonlinear magneto-optical rotation. The\nupper bound of sample length is found from the criterion that the pulse\nself-steepening and group-advance time are observable without pulse distortion\ncaused by the group-velocity dispersion.",
"arxiv_id": "physics/0209036",
"authors": [
"R. G. Ghulghazaryan",
"Yu. P. Malakyan"
],
"categories": [
"physics.class-ph",
"physics.gen-ph"
],
"doi": "10.1103/PhysRevA.67.063806",
"title": "Superluminal optical pulse propagation in nonlinear coherent media",
"url": "https://arxiv.org/abs/physics/0209036"
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