METHOD AND APPARATUS FOR GENERATING AND CONTROLLING SPIN PROPAGATION USING ONE OR MORE COHERENT LIGHT BEAMS

摘要

The present invention uses quantum interference of one and two photon absorption from a multiple color fields to optically inject ballistic spin currents in unbiased photoconductors. The spin currents can be generated with and withou t an accompanying electrical current and can be controlled using the relative phase of the colors. In one aspect of the there is provided a method of generating spin currents in a photoconductor material comprising producing a first coherent light beam having a first frequency .omega.1 and a second coherent light beam having a frequency twice the first frequency 2.omega.1, polarizing the first and second coherent light beams to have a preselected polarization with respect to each other, and simultaneously irradiating a selected region of the photoconductor material with the first coherent light beam and the second coherent light beam to generate a spin current in the photoconductor. When t he photoconductor has a noncentrosymmetric zincblende (T d symmetry) crystal structure a single coherent light beam can be used to obtain pure spin currents and mixed electrical and spin currents may be produced when the photoconductor has a wurtzite structure.