Spin control by ultra short laser pulses in a Mn doped quantum dot

Reiter DE, Axt VM, Kuhn T

Abstract

Optically induced spin flip processes in quantum dots doped with a single Mn atom are discussed. On the femtosecond time scale the exciton can be controlled by ultra short laser pulses. Via the exchange interaction on the Mn spin can flip on a picosecond time scale by transferring its angular momentum to the exciton. For a heavy hole system this flipping process can be described in terms of exchange induced Rabi oscillations between the bright and dark exciton state accompanied by a flip of the Mn spin. Because of the energy splitting between bright and dark excitons the Rabi oscillations are off-resonant and a series of laser pulses is required to achieve a complete flip. When a light hole exciton is resonantly excited in addition to the heavy hole exciton we show that a flip of the Mn spin by two can be achieved by a series of light pulses while the exciton system returns to its initial state. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim