skip to content

Centre for Photonic Devices and Sensors


John Carroll is an Emeritus Professor at Cambridge where he became a lecturer in 1967 and subsequently a Director of Studies at Queens' College, Reader, Professor, Head of B Division, Chairman of the Council of the School of Technology and member of the General Board before retiring in 2001. He has been a chairman of the local IEE section, Editor of the IEE Journal "Solid State Electron Devices" and has served on the IEE Accreditation Board. He is currently a Life Fellow of Queens' College and a Fellow of the Royal Academy of Engineering.

After graduation as a Wrangler he was offered jobs as a 'tame mathematician' but found more interest in untamed experimental research work in the Engineering Department under Professor Bill Beck on microwaves and low noise electronic 'Adler' amplifiers in glass envelopes all of which he designed and built himself. He then worked for six years at the Services Electronic Research Laboratory where he started making GaAs Gunn diode oscillators before moving back to Cambridge. Here he initiated work on silicon Impatts and Trapatts with several outstanding research students working closely with the research department of STL at Harlow. His first book, on Hot Electron Microwave Generators, was written in the late 1960s. Over some forty years, his interests have remained with semiconductors and Maxwell's electromagnetic phenomena moving up in frequency from microwaves to optics and photons. His last book was on Distributed Feedback Lasers (written in conjunction with Dr. James Whiteaway of Nortel and Dr. Richard Plumb of CUED). This won the IEE Rayleigh book prize in 1999.

He is currently working on:

  • Geometric Algebra and Maxwell's equations along with enquiring how one can represent a photon using classical Maxellian theory. An invited paper on this last topic was given at SPIE, San Diego, in 2009
  • A current problem is to show that true single photons do not exhibit dispersion and investigate if such a discovery might further photonic communications