Ultraslow light (<200m∕s) propagation in a semiconductor nanostructure

We report time-domain measurements of ultraslow light propagation in a semiconductor quantum-well structure using coherent population oscillation. Delays greater than 1 ns are achieved for an amplitude-modulated optical beam propagating through a 195-nm-long active region, corresponding to group velocities less than 200m∕s. Delays can be easily varied by adjusting the intensity of the control laser. The bandwidth is suitable to delay sub-GHz modulated optical signals.