Nonlinear spectroscopy of coupled quantum dots

Summary form only given. Optically controlled semiconductor quantum dots (QD´s) have featured prominently in many proposals for quantum computing. A key feature in a quantum logic device is optically induced entanglement of electronic states. Recently this has been successfully demonstrated in a two exciton state system. The next step in a scalable quantum logic device requires states in separate dots that can be entangled and detected. In this vein, we move to a coupled quantum well structure grown with interface fluctuations and use nano-optical probing to carry out the experiments on a vertically coupled QD system. Our approach is based on naturally formed, interface fluctuation QD´s in a double layered 62 /spl Aring/ GaAs quantum well seperated by a 125 /spl Aring/ Al/sub 0.3/Ga/sub 0.7/As barrier.