Gwyn P. Williams

Image of
          Gwyn Williams
Photo taken October 2012


 Gwyn P. Williams                                                                                                           
Jefferson Laboratory
12000 Jefferson Avenue - Suite 21
Newport News, VA 23606
gwyn at

My science is based at Jefferson Lab in Newport News, Virginia. I am also an adjunct faculty member at Hampton University and the College of William and Mary.  Since obtaining my PhD from Sheffield University in the UK in 1971, I have co-authored over 260 research publications, and also written several book chapters.  I was the 1990 co-recipient of an R&D 100 award for developing a wavefront dividing interferometer for use with ultrabright sources.  I am a Fellow of the American Physical Society.

My research has involved understanding the fundamental physical behavior of materials as determined by photoemission studies of the electronic structure, and infrared studies of the vibrational dynamics of adsorbates.  This research has motivated a lifelong parallel development of ultra-bright light sources as probes, a path that took me to the Daresbury synchrotron (NINA), Tantalus, NSLS and to JLab's FEL. I built vuv/soft x-ray facilities at the NSLS and initiated infrared synchrotron radiation activities there.  At Jefferson Lab I helped develop the THz regime using the ultrafast facilities that are part of the FEL facility.   Current research programs involve ultrafast pump-probe dynamics of novel materials and of bonding vibrational modes in both time and frequency domains.  4th generation light sources are a key tool for such studies, and I have been involved with a team that has proposed an extension of the JLab FEL into the electronic excitation region, 10 - 100 eV in the fundamental, with useful harmonics up to 500 eV.

The bulk of my career has been at the national labs, 5 as a user at Daresbury Lab, 21 years on the staff of  Brookhaven National Laboratory in New York, and 14 at Jefferson Lab in Virginia.

 Jefferson Laboratory is in Newport News, Virginia and operates a Free Electron Laser which is among the first of the 4th generation light sources to be operating in the USA, another being the LCLS at SLAC.  The JLab FEL runs at a very high repetition rate and is capable of high average as well as peak power because it uses superconducting radio-frequency cavities and re-circulates the electron beam with energy recovery.  The FEL initially ran in the infrared, but recently we have been driving to higher photon energies, and with harmonics are now the brightest source in the vacuum ultraviolet region where there are no table-top lasers at all.

Specifically the Jefferson Lab FEL is a sub-picosecond, tunable light source covering the range down to 124 nm in the vacuum ultraviolet using harmonics,  and running from 350 nanometers in the fundamental to 14 microns in the mid-infrared.  Pulse energies are up to 300 microJoules, and repetition rates can go up to 75 MHz. Not all parameters can be satisfied simultaneously but average powers in excess of 10 kW have been demonstrated in the infrared.  We also have a high power broadband THz laboratory whose source is the electron beam in the FEL.  This is a broadband source covering the range 0.1 - 5 THz and with an average power of 100 watts.

Here is my google_scholar profile.

Here's a list of my publications.

Brief Resume:

2000 – present              Jefferson Lab

1979-2000                    Brookhaven National Laboratory

1977-1979                    Montana State University

1971-1977                    Leicester University (UK)

1971    PhD                  Sheffield University (UK)

1968    BSc                  Hull University (UK)


Lots of people ask me about the Binding Energies of the Elements, for which I welcome any updates by e-mail, see address above.  I put the data into a periodic table based on an idea of Cliff Olson, which is available as a 24"x36" poster pdf format.
When I am not doing physics I am often calling folk dances (called contradances), or even dancing.
Last updated October 4, 2013