Abstract
We consider pulse propagation in a linear anomalously dispersive medium where the group velocity exceeds the speed of light in vacuum ( ) or even becomes negative. A signal velocity is defined operationally based on the optical signal-to-noise ratio, and is computed for cases appropriate to the recent experiment where such a negative group velocity was observed. It is found that quantum fluctuations limit the signal velocity to values less than .
- Received 3 November 2000
DOI:https://doi.org/10.1103/PhysRevLett.86.3925
©2001 American Physical Society