Multipolar Interband Absorption in a Semiconductor Quantum Dot: Electric Quadrupole Enhancement

LLE Review, Volume 91 139 Introduction A quantum dot is an artificially created semiconductor structure in the size range of 5 to 100 nm. As a whole, it behaves like an atom since the quantum effects of the confined electrons are enlarged with respect to the interactions of the electrons inside each atom. Since the conception of quantum dots in the early 1980s, the study of their physical properties continues to be a very active field of research. Quantum dots can now be synthesized by various methods and have a multitude of potential technological applications, which include lasers with high optical gain and narrow bandwidth, and wavelength tunability.1 Also, dipole–dipole interaction between neighboring quantum dots is being explored for applications in quantum computing.2 Furthermore, quantum dots are potential singlephoton sources, which may be used to create nonclassical electromagnetic states.3