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We investigated quantum size effects on polarized photoluminescence (PL) from a-plane Cd0.06Zn0.94O/ZnO quantum wells (QWs) with different well widths (LW). The degree of polarized PL at 300 K increased with a narrowing of LW, which obeyed the polarization selection rule based on a Boltzmann-like distribution. Furthermore, the narrowing of LW enhanced the anisotropic lattice distortions in well layers along the growing direction, which resulted in an increase of energy separation between the two topmost valence band levels. The effect of quantum confinement on polarized PL of QWs was accompanied by a change of structural symmetry of the well layers. [ABSTRACT FROM AUTHOR]

We have found that a chiral twist defect inserted in a cholesteric elastomer gives rise to circularly polarized localized modes of both handedness. This defect enhances the resonant mode amplitude whose handedness is opposite to that of the cholesteric helix for high cross-linked density, whereas for low cross-linked density, the same mode is decoupled with the defect and thus the resonant mode disappears. Finally, the resonant mode of the same handedness as the elastomer helix is maintained for both high and low cross-linked density. [ABSTRACT FROM AUTHOR]