Colloquia & Guest Speakers

Laser Physics in the Extreme: Ultrahigh Intensities

Barry Walker, University of Delaware

Monday, February 16, 2015
3 p.m.–4 p.m.

Goergen 101, Sloan Auditorium


Over the past twenty years, interactions of intense lasers with atoms and molecules have measured the laser electric field in time, generated coherent attosecond (10^(-18) s) pulsed x-ray light, probed multielectron excitation, and performed molecular tomography. Current laser technology exceeds the intensity at which these observations were made by ten-thousand times. Up to twenty-six electrons with energies extending from keV to MeV have been ionized by new, 10^(19) W/cm^2, ‘ultra’ intense lasers. We discuss experiments and theory on the interaction of ultrahigh intensities with atoms and molecules. The research contributes to our understanding of ultrastrong field dynamics, excitation, and multi-electron physics as well as the underpinnings for next generation radiation sources and plasma physics in ultrastrong fields.


Barry Walker is a professor in the Department of Physics and Astronomy at the University of Delaware. His PhD is from State Univ. of New York at Stony Brook. His work earned the APS Best Thesis Prize in Atomic Molecular and Optical Physics. His post-doc was at the University of California at San Diego where he built one of the first systems ultrafast 25fs laser systems to reach 60 terawatts of peak power.

Barry’s current expertise is in ultra-high intensity interactions. His group publishes both experimental and theoretical work and his research has been cited more than 3,000 times. In 2011 he was elected as a Fellow of the American Physical Society for investigations of multiple ionization in the non-relativistic and relativistic regimes that have contributed to the understanding of intense laser-atom interactions. In 2014 he chaired the Multiphoton Gordon Conference on Multiphoton Processes and in 2016 he will Chair the Mid-Atlantic Section Meeting for the American Physical Society.

His teaching ranges from graduate to undergraduate and currently involves Physical Optics for Engineering and Physics and Physics I for Pre-Med and Life Sciences.