Extreme Optics: When Quasiparticles Collide, and 1+1=11

Event Date: 

Tuesday, May 1, 2012 - 4:00pm

Event Location: 

  • Broida 1640

Event Contact: 


Mark Sherwin - UCSB

Intense laser fields can rip electrons from an atom and slam them back into it.  By using intense terahertz radiation from UC Santa Barbara’s Free-Electron Lasers, we have observed an analogous phenomenon for photo-excited electrons and holes in a semiconductor. A trillion energetic electron-hole collisions per second convert a monochromatic near-infrared laser beam at 350 THz(0.8 µm) into a polychromatic near-infrared beam containing up to 11 new frequencies spaced by 1 Terahertz.  Implications for the nature of optical excitations in solids and possible applications to optical communications will be discussed.