Alan Fisher is a Staff Scientist at SLAC National Accelerator Laboratory in Menlo Park, California, a U.S. Department of Energy laboratory operated by Stanford University. After receiving a Ph.D. in physics at the Massachusetts Institute of Technology in 1983, he worked at Stanford and then at Brookhaven National Laboratory on free-electron lasers with thermionic and photocathode rf guns, and on photocathode drive lasers. He moved to SLAC in 1994 to oversee beam diagnostics for the PEP-II electron-positron collider, and now works on the Linac Coherent Light Source x-ray FEL and on the Facility for Advanced Accelerator Experimental Tests. As a visitor at CERN, he worked with the Beam Instrumentation group to develop synchrotron-light diagnostics for the LHC proton beams. His current focus is terahertz radiation from SLAC electron beams.