Dressed States in Atoms and in Excitons

Monique Combescot

Christian Tanguy, Monique Combescot

Unlike the energy shift which has, at large detuning, the same dressed-atom value for all excitonic states and all space dimensions, we show that the relative change of the dressed-exciton absorption strength is the dressed-atom one multiplied by 1-d for every exciton level, d being the space dimension. The analytical derivation of this striking result uses an extension of Dalgarno's method to an arbitrary exciton level.

Piers Coleman

S. J. Boyle, A. J. Ramsay, A. M. Fox +3 more

We report picosecond control of excitonic dressed states in a single semiconductor quantum dot. A strong laser pulse couples the exciton and biexciton states, to form an Autler-Townes doublet of the neutral exciton transition. The Rabi-splitting, and hence the admixture of the dressed states follows the envelope of the picosecond control laser. We create a superposition of dressed states, and observe the resulting beat: a direct measurement of a Rabi oscillation in time delay rather than the usual power domain.

Claire Le Gall, A. Brunetti, H. Boukari +1 more

We report on the observation of spin-dependent optically dressed states and the optical Stark effect on an individual Mn spin in a semiconductor quantum dot. The vacuum-to-exciton or the exciton-to-biexciton transitions in a Mn-doped quantum dot are optically dressed by a strong laser field, and the resulting spectral signature is measured in photoluminescence. We demonstrate that the energy of any spin state of a Mn atom can be independently tuned by using the optical Stark effect induced by a control laser. High resolution spectroscopy reveals a power-, polarization-, and detuning-dependent Autler-Townes splitting of each optical transition of the Mn-doped quantum dot. This experiment demonstrates an optical resonant control of the exciton-Mn system.

Leonid V. Keldysh