Enhanced index and negative dispersion without absorption in driven cascade media

Journal Article · Thu Apr 01 04:00:00 EST 2004 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.69.043812· OSTI ID:20641052

Xiangming, Hu; Jun, Xu ^[1]

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1. Department of Physics, Huazhong Normal University, Wuhan 430079 (China)

In this paper we investigate the dispersive and absorptive properties of a system of three-level cascade atoms driven by a strong coherent field. Three characteristic features are found. First, for the same set of atom-light interaction parameters, the indices of refraction are large at three different frequencies where the absorption vanishes. These three frequencies are determined by the resonance transition frequencies between dressed states produced by the strong driving field. Second, negative dispersion without absorption, which leads to superluminal light propagation, is achievable in the central resonance structure of the dispersion spectrum. Third, the whole absorption spectrum displays, in general, three pairs of absorption peaks and three pairs of gain (negative absorption) peaks. The minimal spacing between dressed states determines whether the outer adjacent gain peaks are separated from each other.

• OSTI ID: 20641052
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 4 Vol. 69; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION
ABSORPTION SPECTRA
ATOMS
GAIN
LIGHT TRANSMISSION
OPTICAL DISPERSION
OPTICS
PHOTON-ATOM COLLISIONS
QUANTUM MECHANICS
REFRACTION
REFRACTIVE INDEX
RESONANCE
VISIBLE RADIATION