Superluminal propagation of an optical pulse in a Doppler-broadened three-state single-channel active Raman gain medium

Abstract

Using a single-channel active Raman gain medium, we show a $220\ifmmode\pm\else\textpm\fi{}20\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$ advance time for an optical pulse of ${\ensuremath{\tau}}_{\mathit{FWHM}}=15.4\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{s}$ propagating through a $10\phantom{\rule{0.3em}{0ex}}\mathrm{cm}$ medium, a lead time that is comparable to what was reported previously using a two-mode pump field. In addition, we have verified experimentally all the features associated with this single-channel Raman gain system.