Transient nonlinear spectroscopy of excitons and biexcitons in single quantum dots

Transient nonlinear spectroscopy is used to study excitons and biexcitons confined to single interface fluctuation quantum dots (QD’s). Exciton lifetimes measured by this technique are found to be between 25 and 50 ps, depending on the QD studied. Biexciton binding energies and polarization selection rules agree with previous measurements from cw nonlinear spectroscopy, and biexciton lifetimes are found to be half of the exciton lifetime for the same quantum dot. The ability to perform transient nonlinear spectroscopy of excitons and biexcitons in single quantum dots is an important step towards the development of solid state quantum computing based on interacting excitons in quantum dots.