Optoelectronic Manipulation of Spin in Semiconductors

Abstract

In contrast to metals, an additional degree of freedom afforded by semiconductor spintronics allows direct optical access to electronic and nuclear spin states. During the last few years, optical measurements have demonstrated that it is possible to create, manipulate, transport, and store electron spin coherence in a variety of solid state materials. In addition, controlled interactions with nuclear moments via coherent electron spins have suggested the possibility of high density quantum storage at the nuclear level. A number of laboratories have developed research programs aimed at engineering a new generation of optoelectronic devices using a coherent ensemble of long-lived spin states (electron or nuclear) in which the direction or phase of the ensemble can be rapidly manipulated optically or electronically. This offers the potential of high performance optoelectronics, using the Faraday rotation produced by the ensemble, with very high speed optical switches, modulators, encoders, and decoders as candidate devices. The intrinsic speed of these devices may be in the femtosecond regime, and the power required to change the phase may be small if the phase of the spin ensemble can be manipulated by moving it within spin-engineered semiconductor heterostructures having differing g factors.