Open AccessObservation of large group index enhancement in Doppler-broadened rubidium vapor
Author(s) -
Bo-Xun Wang,
Chih-Yuan Liu,
D. J. Han
Publication year - 2015
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.018792
Subject(s) - hyperfine structure , rubidium , optics , doppler effect , interferometry , atomic physics , absorption (acoustics) , refractive index , physics , phase (matter) , materials science , potassium , quantum mechanics , astronomy , metallurgy
We report experimental observation of large group index across the Lamb dips of ground hyperfine states in Doppler-broadened 87Rb vapor. By sweeping the laser frequency through each hyperfine transition we measure the saturated absorption and optical phase shift using a phase-locked Mach-Zehnder interferometer. Our measurements provide a direct demonstration of the theoretical prediction by Agarwal et al. [G. S. Agarwal and T. N. Dey, Phys. Rev. A 68, 063816, (2003)] for the first time. An enhancement factor as large as 1005 in group index was observed for Rb vapor at temperature of 85 °C. The experimental data are in good agreement with the theory.