Phase and velocity sensitivity of surface plasmon polaritons at the interface of atomic and nano-composites media

The phase and velocity sensitivity is calculated at the interface of three level atomic medium and a Silver Silica (AgSiO2) nano-composites material by surface plasmon polaritons waves. A large kink in the real part of dispersion relation of SPPs is measured in the large interaction zone, due to which the group velocity and delay/advance times of SPPs are enhanced. A group velocity of v ( g ) = +/- 1 x 10(9) m s(-1) is measured at the group index region of 0 n ( g ) n ( g ) t ( g ) = +/- 1 x 10(-7) s at the propagation length L ( x )(m) and at v ( g ) = +/- 1 x 10(9) m s(-1) in the range of group index of 0 n ( g ) n ( g ) < 0. The volume fractional change of nano particles, probe/control field detuning and Rabi frequency of control field significantly influence the velocity sensitivity. The velocity sensitivity is measured to be 23 mu m s(-1) by SPPs. The velocity sensitivity could be improved to 0.1 mu m s(-1) by taking large ensemble of atomic coherence and large delay/advance in time due to SPPs.