Femtosecond Coherent Optical Control of Electronic and Magnetic Order

Note: Pizza served at 11:45 AM
Speaker: Ilias Perakis, University of Crete

When: February 17, 2012 (Fri), 12:00PM to 01:00PM (add to my calendar)
Location: SCI 352
Hosted by: Richard Averitt

This event is part of the Biophysics/Condensed Matter Seminar Series.

Abstract: The idea of using femtosecond laser pulses to control material properties at the quantum level has led to some exciting developments at the frontier of condensed-matter physics and materials science. Interactions among coupled degrees of freedom make it possible to switch and modulate electronic and magnetic properties in new ultrafast ways by using photons. Recent advances in laser technology provide access to non-equilibrium many-body states and non-thermal phases. Prominent examples that challenge our present understanding are femtosecond photoinduced phase transitions and femto-magnetism. In this talk I will discuss a non-equilibrium theory that engages the elements of transient coherence, correlation, and nonlinearity to address the following fundamental questions in different systems:

  • What happens during the coherent nonlinear photoexcitation of a correlated system?
  • What is the nonlinear optical and magneto-optical response to this photoexcitation?
  • What non-equilibrium many-body mechanisms govern the non-thermal temporal regime?
  • Which experimental schemes can best visualize the resulting transient phases?

This theory is tightly integrated with femtosecond nonlinear optical and magneto-optical spectroscopy experiments. I will present recent results in three model systems: ferromagnetic (III,Mn)V semiconductors,  two- dimensional electron gas in a strong magnetic field, and the manganites. I will also discuss some possible applications for all-optical magnetic memory control at THz speeds.