Knight is Senior Research Investigator at Imperial College. He retired in 2010 as Deputy Rector (Research) at Imperial but remains an Emeritus Professor. He was knighted in 2005 for his work in optical physics. Knight was the 2004 President of the Optical Society of America and a past President of the Institute of Physics. He is Editor of Contemporary Physics, Chair of the UK National Quantum Technology Programme Strategy Advisory Board, chairs the Quantum Metrology Institute at the National Physical Laboratory, was until 2010 chair of the UK Defence Scientific Advisory Council and remains a UK Government science advisor. His research centres on quantum optics and quantum technology. He has won the Thomas Young Medal and the Glazebrook Medal of the Institute of Physics, the Ives Medal and the Walther Medal and Prize of the OSA, the Faraday Medal of the IET and the Royal Medal of the Royal Society.