Dark exciton preparation in a quantum dot by a longitudinal light field tuned to higher exciton states

Several important proposals to use semiconductor quantum dots in quantum information technology rely on the control of the dark exciton ground states, such as dark exciton based qubits with a microsecond lifetime. In this paper, we present an efficient way to occupy the dark exciton ground state by a single short laser pulse. The scheme is based on an optical excitation with a longitudinal field component featured by, e.g., radially polarized beams or certain Laguerre-Gauss or Bessel beams. Utilizing this component, we show within a configuration interaction approach that high-energy exciton states composed of light-hole excitons and higher dark heavy-hole excitons can be addressed. When the higher exciton relaxes, a dark exciton in its ground state is created. ; Fil: Holtkemper, M. Westfälische Wilhelms Universität; Alemania ; Fil: Quinteiro, Guillermo Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Modelado e Innovación Tecnológica. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Modelado e Innovación Tecnológica; Argentina ; Fil: Reiter, Doris E. Westfälische Wilhelms Universität; Alemania ; Fil: Kuhn, Tilmann. Westfälische Wilhelms Universität; Alemania