Electronic transitions in disk-shaped quantum dots induced by twisted light

Abstract

We theoretically investigate the absorption and emission of light carrying orbital angular momentum (twisted light) by quasi-two-dimensional (disk-shaped) quantum dots in the presence of a static magnetic field. We calculate the transition matrix element for the light-matter interaction and use it to explore different scenarios, depending on the initial and final states of the electron undergoing the optically induced transition. We make explicit the selection rule for the conservation of the z projection of the orbital angular momentum. For a realistic set of parameters (quantum dot size, beam waist, photon energy, etc.) the strength of the transition induced by twisted light is 10% of that induced by plane waves. Finally, our analysis indicates that it may be possible to select precisely the electronic level one wishes to populate using the appropriate combination of light-beam parameters suggesting technological applications to the quantum control of electronic states in quantum dots. © 2009 The American Physical Society.