· Director, NSF Center for Energy Efficient Electronics Science (E3S)2010–2021
· Professor Emeritus and Professor of Graduate School, University of California, Berkeley2007–
· Professor of Electrical Engineering, University of California, Los Angeles (UCLA)1993–2007
· Director of Solid-State Physics Research, Bell Communications Research1984–1993
· Research Associate and Head of Optical Sciences Group, Exxon Research Center1979–1984
· Associate Professor of Applied Physics, Harvard University1976–1979
· Assistant Professor of Applied Physics, Harvard University1974–1976
· Research Scientist, Bell Telephone Laboratories1972–1974
· Ph.D. in Applied Physics, Harvard University1972–
· Teaching Fellow, Harvard University1971–1972
· A.M. in Applied Physics, Harvard University1969–
· B.Sc. in Physics, McGill University1967–