Polarization dependence of optical absorption and emission in quantum wires

The polarization dependence of absorption and emission spectra in cylindrical quantum wires is studied using a formulation of multiband envelope-function theory in a representation of cylindrical Bloch waves. The work presented is an analysis of the optical properties of quantum wires, which includes band-coupling effects. Contrary to the assumptions employed in previous studies, the valence states involved in these transitions are a strong admixture of light- and heavy-hole character. Band-coupling effects are therefore essential to understanding valence-subband dispersion and density of states, the energy dependence of interband optical-transition matrix elements, and polarization anisotropies. Analytical expressions are derived for the polarization dependence of optical matrix elements, and hence, optical-absorption and emission spectra. Applicability of the results derived for cylindrical quantum wires to the case of wires with lower symmetry is discussed.