Answers are grounded in this paper and cite their sources.
It is found that ultrashort pulses in a high-gain 3.51-{μ}m xenon laser propagate through the amplifying medium at a velocity less than the vacuum speed of light by as much as a factor of 2.5. The pulse velocity is a function of the gain and agrees with the group velocity.
No takes yet. Share an insight, caveat, or question.
Casperson et al. (1971) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: