Elliptical Polarization of Localized States in an Anisotropic Single GaAs Quantum Ring

Localized states in an anisotropic single GaAs quantum ring were investigated in terms of polarization dependence of micro-photoluminescence spectrum at 5K. Given four Stokes parameters measured with a pair of linear polarizers and waveplates, the elliptical polarization states of two different vertical confinement states ([Formula: see text] and [Formula: see text]) were compared with phase, rotation, and ellipticity angles. While the polarized emission intensity of the [Formula: see text] states becomes enhanced along [1,1,0] compared to that along [1, [Formula: see text] ,0], the polarization asymmetry of the [Formula: see text] states shows the opposite result. We conclude the polarization state is determined by the shape of the lateral wavefunctions. In the [Formula: see text] state, crescent-like wavefunctions are strongly localized, but the [Formula: see text] state consists of two crescent-like wavefunctions, which are connected weakly through quantum tunneling.