Richard Williams Reynolds Professor, Physics Dept., Wake Forest University
	212 Olin Physical Laboratory P.O. Box 7507 Winston-Salem, NC 27109-7507	Telephone: 336-758-5132 Fax: 336-758-6142 E-mail: williams@wfu.edu

Teaching

• (Spring 2005) -- PHY 113, General Physics
• (Spring 2005) -- PHY 715 Nonlinear Optics & Quantum Electronics
  
• (Fall 2005)     -- PHY 352/652, Physical Optics and Optical Design
  

• PHY 354/752 -- Solid State Physics
• PHY 715 -- Nonlinear Optics and Quantum Electronics
• FYS 100 --  First Year Seminar, "Understanding Stuff:  the materials of our world and of our selves"
  

Research

Ultrafast and Very Small:	Subpicosecond and Submicrometer Phenomena in Condensed Matter Physics // NSF DMR-9732023

We use ultrafast spectroscopy to investigate the immediate consequences of absorption of a photon by a crystalline solid. Ultrashort (~130 fs) high-power (~ 20 Gw) laser pulses are employed to create an electronic excitation of the solid and monitor its evolution within the coupled electron-lattice system. Phenomena of interest include self-trapping of excitons and of charge carriers in insulators, relaxation of hot carriers and surface state dynamics in semiconductors, and excitonic processes of lattice defect formation.  The onset of infrared absorption due to small electron polarons in lithium niobate is being investigated.  Nonlinear optical and ultrafast phenomena are studied in inhomogeneous samples and thin films with 3-dimensional spatial resolution of the order 200 nm x 700 nm using confocal multiphoton microspectroscopy.  Interactions at surfaces are investigated using ultrahigh vacuum analytical techniques such as fs time-resolved photoelectron spectroscopy.  Surface defects on CdSe are under investigation.   ZnO is a material of current interest for development of electronic and optical devices.  Thin film deposition and optical characterization are carried out in our laboratory.

Zinc Oxide: Publications Gang Xiong, John Wilkinson at the pulsed laser deposition station

time-resolved spectroscopy thin film deposition giant oscillator strength

Recent Collaborative Projects

Research on Characterization of point defects and their spatial distributions in III-V semiconductors with 2001 visiting Fulbright Scholar Prof. Sebahattin Tuzemen.

Recent Publications

Graduate Students

• Jerry Kielbasa
• Yong Qiu

Recent:

• Gang Xiong (Ph.D. 2004; now at Pacific Northwest National Laboratory, Richland, WA)
• Yonas Abraham (Ph.D. 2004; now at Targacept, Inc., Winston-Salem, NC)
• John Wilkinson (Ph.D. 2003; now Postdoc at Naval Research Laboratory, Washington DC)
• Difei Liang
• Hank Yochum  (Ph.D.; now Assistant Professor and Chair, Physics Department, Sweetbriar College, Lynchburg VA)
  
• Yaochun Zhang (Ph.D.; now systems analyst at Sara Lee Corp., Winston-Salem NC)