Nonlinear optics with ballistic charge and spin currents in semiconductors

Date: 
Monday, May 16, 2011 -
4:00pm to 5:00pm
Speaker: 
Hui Zhao
Speaker's Institution: 
University of Kansas

Electronic transport on nanometer dimensions is of fundamental importance in semiconductor nano-electronics. In this talk I will discuss our recent experimental studies of ballistic charge and spin transport on nanometer length scales by using ultrafast nonlinear optical techniques. I will discuss optical injection of ballistic currents through a coherent control technique utilizing quantum interference between one-photon and two-photon absorption pathways. I will then describe how to study the dynamics of these ballistic currents by tracking the position of the carriers with 100 femtosecond temporal resolution and sub-nanometer spatial resolution. I will discuss second-order nonlinear optical effects induced by the spin and charge currents, and show that these effects can be used for a direct, nondestructive, and real-time imaging of these currents.