Professor Marshall received his Ph.D. in physics from the University of Illinois in 1960 and joined Columbia University in 1962 as a professor in the Department of Electrical Engineering. He became a Professor of Engineering Science in 1970 and was a member of the Plasma Physics Committee where he launched groundbreaking experimental research into the physics of plasmas, relativistic electron beams, and free electron lasers.
Professor Marshall was one of the nine founding faculty members of the Department in 1978, becoming one of Columbia's first Professors of Applied Physics. He was awarded Columbia’s Great Teacher Award in 1995. During his forty-four years at Columbia University, he has supervised or co-supervised 44 doctoral students. During the decade before he retired in 2006, Professor Marshall was the dedicated faculty advisor to our students in the Medical Physics Program.
Working with his students and colleague Professor Perry Schlesinger, Professor Marshall pioneered the development of free electron lasers (FEL), which have been shown to generate very large amounts of power, tunable in bands from the microwave to the visible spectrum and beyond. In the 1970's, the first FEL in the Raman regime was demonstrated in Marshall's Lab. Professor Marshall's research also included FEL photonics and led to the production of TW-level ultra-short pulses of radiation. In 1985, he published Free Electron Lasers, which provided the first integrated treatment of the operation and characterization of the free-electron laser.
Between 1985-87, he served on the APS Study Group on the Science and Technology of Directed Energy Weapons. Called by many "the most important APS study ever done", this study provided a clear technical assessment of the severe limitations of existing candidates for DEWs such as high intensity lasers and energetic particle beams.
FEL physics has a close relationship with laser and accelerator physics, and his research focus included innovation accelerator physics. Professor Marshall explored new methods of accelerating particles using Brookhaven's Accelerator Test Facility (ATF). In 1999, Marshall proposed the dielectric wake field accelerator. Working with his colleague, Jay Hirshfield, Professor Marshall continued his research at the ATF where he established the fundamental physics of dielectric wake field acceleration. Although retiring from academic duties in 2006, Professor Marshall continued to apply his insights and pursue his remarkable discoveries in beam and accelerator physics and published his last paper in 2018.