Phase sensitivity by fast light propagation using compton scattering and Kerr non-linearity

Abstract

We theoretically investigated the sub-luminal and super-luminal light propagation by introducing compton scattering and Kerr non-linear effects to a four level atomic system. Slow light propagation is observed at a group index of 3918 in the transparency region. The slow light propagation is tuned to fast light propagation at group index 0.2, using compton scattering angle of varphi =pi /6. The surperluminality is further enhanced with compton scattering angle at the resonance frequency. Under the Kerr nonlinearity, the slow light propagation at a group index of 3918 is enhanced to fast light propagation at group index of 2times 10^6 at the resonance frequency. The group index is reduced to 6.56281times 10^{-5} in the presence of both Kerr non-linearity and compton scattering. In the presence of compton scattering, the Phase shift at pi /2 without Kerr nonlinearity is 7times 10^{-8} radian and with Kerr nonlinearity its value is 1.7times 10^{-9} radian at resonance frequency. This demonstrate that introducing Kerr effect and compton scattering lead to significant modifications in the phase shift.