Optical control of spin coherence in singly charged (In,Ga)As/GaAs quantum dots

Phys Rev Lett. 2006 Jun 9;96(22):227401. doi: 10.1103/PhysRevLett.96.227401. Epub 2006 Jun 7.

Abstract

Electron spin coherence has been generated optically in n-type modulation doped (In,Ga)As/GaAs quantum dots (QDs) which contain on average a single electron per dot. The coherence arises from resonant excitation of the QDs by circularly polarized laser pulses, creating a coherent superposition of an electron and a trion. Time dependent Faraday rotation is used to probe the spin precession of the optically oriented electrons about a transverse magnetic field. The coherence generation can be controlled by pulse intensity, being most efficient for (2n+1)pi pulses.