  Using a single-particle atomistic pseudopotential method followed by a
many-particle configuration interaction method, we investigate the geometry,
electronic structure and optical transitions of a self-assembled InAs/GaAs
quantum ring (QR), changing its shape continously from a lens-shaped quantum
dot (QD) to a nearly one dimensional ring. We find that the biaxial strain in
the ring is strongly asymmetric in the plane perpendicular to the QR growth
direction, leading to giant optical anisotropy.
