Yan XIE 
Beijing Computational Science Research Center
Abstract: In the recent decade, the study of nonlinear optics in semiconductor quantum dots (QDs) makes people find many new ways to control the nonlinear optical properties, and some of them play an important role in laser frequency conversion and quantum information processing. The generation of harmonic emission in QDs, as one of nonlinear optical phenomena, can work as a tunable coherent optical source, as shown in our previous study. Recently, we find that the polarization state of high-order harmonics can also be controlled in QD systems. In order to reveal the mechanism of the polarization conversion, we investigate the dynamic process by mapping the optical process to a particle transport process of a three-chain system. Using this method, we reveal the fact that the polarization conversion results from the effect of coherent destruction of tunneling (CDT) during the transport process. And it also provides a clear physical picture to help us better understand how the phase difference around ±π/2 occurs when the CDT happens.

Location: 606 Conference Room
Date and time: Nov 18, 2011   14:30