Physical review. B, Condensed matter
Direct observation of an ac Stark splitting in semiconductor microcavities excited above the continuum onset
Francesco Quochi, Michele Saba, Cristiano Ciuti, Ross P. Stanley, R. Houdré, U. Oesterlé, Jean Louis Staehli, B. Deveaud, Giovanni Bongiovanni, Andrea Mura
Abstract
We study the coherent optical response of a very high-finesse microcavity with a single quantum well by means of degenerate subpicosecond pump-probe spectroscopy. The dynamics of the ac Stark effect versus pump intensity is investigated upon tuning the empty-cavity mode below and above the exciton transition energy, at the exciton continuum onset. The evolution from a simple dynamical excitonic shift to a dynamical splitting is clearly observed in both cases. The qualitative agreement with numerical calculations based on the semiconductor Maxwell-Bloch equations is good.