Evidence for intervalence band coherences in semiconductor quantum wells via coherently coupled optical stark shifts - art. no. 237402

We report the experimental observation of coherently coupled heavy-hole-lig ht-hole Stark shifts, i.e., light-hole exciton shifts under heavy-hole exci ton pumping conditions, in InGaAs quantum wells. The theoretical analysis o f the data is based on a full many-body approach (dynamics-controlled trunc ation formalism) in the third-order nonlinear optical regime. It is shown t hat the Stark shift data can be interpreted as strong evidence of suitably defined nonradiative intervalence band coherences in a semiconductor quantu m well. Hence, the observations establish a semiconductor analog of Raman c oherences in three-level atoms.