Journal of Communications Technology and Electronics

The character of the dispersion of the refractive index near an isolated spectral line

Nikolai S. Bukhman, Anastasia Kulikova

Published May 1, 2015• 4 citations

Abstract

An approximate analog of the Kramers-Kronig relationships for an isolated spectral line is proposed. Expressions are obtained for the real part of the dielectric susceptibility of a substance near a spectral line for collisional, Doppler, and time-of-flight spreading of the spectral line. It is shown that, generally, the imaginary part of the complex form-factor of the spectral line attenuates very slowly, namely, according to the hyperbolic law, as the deviation from the center frequency grows. Therefore, even in the case when practically there is no radiation absorption beyond the spectral line, the influence of this spectral line on the refractive index of the substance manifests itself rather far from it.

DOI: 10.1134/s1064226915030080

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