Enhancement of interferometric precision using fast light
  We show that anomalous dispersion characteristic of fast-light can be used to enhance the sensitivity of optical interferometry under certain conditions. In particular, we show that a dual-chamber Fabry-Perot interferometer with a shared mirror-pair can be used in a way so that its sensitivity is increased by operating near the critically anomalous dispersion condition where the group index is much less than unity. The enhancement factor can be as high as 108 for realistic conditions. The process of bi-frequency pumped Raman gain in a lambda-type atomic medium can be used to achieve this effect. 
M.S. Shahriar, R. Tripathi, G.S. Pati, V. Gopal, M. Messall and K.   Salit