Reduction of Light Group Velocity by Coherent Population Oscillation in a Ruby Crystal

We report the investigation of the reduction of the group velocity propagation resulting from the steep change of the refractive index by the coherent population oscillation in a ruby crystal at room temperature. Slow light propagation is observed in a solid-state material at room temperature. The measured delay is about 2.314±0.005 ms, corresponding to a group velocity as slow as 43.215±0.094 m/s in a non-sinusoid modulated waveform. The influences of pulse duration on the delay and the reduction of light propagation are given.