%L discovery45961 %T Fast optical preparation, control, and readout of a single quantum dot spin %V 100 %N 19 %J Physical Review Letters %A AJ Ramsay %A SJ Boyle %A RS Kolodka %A JBB Oliveira %A J Skiba-Szymanska %A AM Fox %A MS Skolnick %A HY Liu %A M Hopkinson %X We propose and demonstrate the sequential initialization, optical control, and readout of a single spin trapped in a semiconductor quantum dot. Hole spin preparation is achieved through ionization of a resonantly excited electron-hole pair. Optical control is observed as a coherent Rabi rotation between the hole and charged-exciton states, which is conditional on the initial hole spin state. The spin-selective creation of the charged exciton provides a photocurrent readout of the hole spin state. © 2008 The American Physical Society. %D 2008 %O © 2008 The American Physical Society