Toni Taylor 

Center for Integrated Nanotechnologies 

Los Alamos National Laboratory 

Ultrafast Dynamics in Complex Materials
 

I will discuss the development and application of novel optical spectroscopic techniques to the study of ultrafast dynamics in complex materials. I will first describe all-optical pump probe and optical-pump far-infrared probe experiments for the investigation of correlated electron materials such as heavy fermions, superconductors and magnetic materials. The experimental techniques are discussed followed by a brief review of ultrafast electron dynamics in conventional wide-band metals that serves as a starting point in understanding dynamics in more complex systems.  Our results show that, in general, ultrafast optical spectroscopy provides a sensitive method to probe the dynamics of quasiparticles at the Fermi level.  We have further extended these measurements to reveal dynamics in structured materials, including self-assembled semiconducting quantum dots and nanostructured semiconductor superlattices. Finally, the interaction of ultrafast optical pulses and microstructured fibers is visualized and studied using novel techniques that simultaneously display the spectral and temporal characteristics of a pulse.  These techniques are used to investigate the nonlinear dynamics associated with the interaction between dispersive waves and solitons in the vicinity of the second zero dispersion point of photonic crystal fibers.