Coherent Coupling between Quantum Dots and a Quantum Well

We present experimental results and corresponding discussion of coherent coupling between photo-excited quantum-dots and a quantum well. The coupling is understood by investigating the dependence of quantum-dot photoluminescence as a function of quantum dot-well barrier thickness. For small thickness of the dot-well barrier, the signal shows an anomalous low intensity behavior. This behavior is explained by sub-picosecond tunneling and electron oscillations between the quantum dot layer and quantum well. As the barrier thickness increases the quantum-dot photoluminescence signal increases at first but then again decreases. This and other unusual behavior of the communication between a quantum-dot layer and quantum well will be discussed.