This article is cited in 9 papers

Interaction of laser radiation with matter. Laser plasma

Deformation of the signal envelope due to a strong dispersion of the refractive index in the gain region

N. S. Bukhman

Samara State Architecture and Building Academy

Abstract: It is shown that, when a narrow-band signal with a non-Gaussian envelope propagates in a medium with a strong dispersion, the signal envelope being distorted due to the dispersion of the gain (or) absorption in the medium. Nevertheless, the amplitude-modulated signal having a symmetric (even) intensity envelope remains the same. The propagation velocity of the `middle point' (i.e., the symmetry centre) of the signal coincides with the real group velocity of the wave with a given carrier frequency in the medium and can be subluminal, superluminal or negative. Therefore, the concept of a real group velocity (including the superluminal or negative velocity) is also applicable in media with a strong dispersion of the gain (or absorption).

PACS: 42.25.Bs

Received: 19.03.2003
Revised: 26.08.2003

 English version: Quantum Electronics, 2004, 34:2, 120–124

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