Optical manipulation of nuclear spin by a two-dimensional electron gas

Conduction electrons are used to optically polarize, detect, and manipulate nuclear spin in a (110) GaAs quantum well. Using optical Larmor magnetomet ry, we find that nuclear spin can be polarized along or against the applied magnetic field, depending on field polarity and tilting of the sample with respect to the optical pump beam. Periodic optical excitation of the quant um-confined electron spin reveals a complete spectrum of optically induced and quadrupolar-split nuclear resonances, as well as evidence for Deltam = 2 transitions.