Stephen J. Sweeney (Senior Member, IEEE) was born in England, in 1973. He received the B.Sc. (Hons.) degree in applied physics and the Certificate in Education from the University of Bath, England, in 1995 and the Ph.D. degree in physics from the University of Surrey, England in 1999. Following Postdoctoral Research Fellow positions working on InGaN LEDs and quantum dot lasers, he became a Lead Scientist for Marconi Optical Components working on the development of fixed frequency and tunable lasers for telecommunications applications. He has spent sabbatical leave with Arizona State University and Philipps-Universität, Marburg in 2008 and was a JSPS International Invitational Fellow with the Kyoto Institute of Technology in 2019. He was an Associate Editor of IEEE Journal of Quantum Electronics from 2014 to 2020. He is currently a Professor of Physics with the Advanced Technology Institute and Department of Physics, the University of Surrey. His current research interests include novel semiconductor materials and devices operating from the visible through to the mid-infrared for applications in displays, communications and energy. In addition to his role with Surrey, he is a Visiting Professorial Fellow with the University of Wollongong, Australia, Chief Technology Officer for ZiNIR Ltd. (U.K.) and the Editor of Journal of Materials Science: Materials in Electronics. He is a Chartered Physicist, a Fellow of The Institute of Physics (U.K.) and a Fellow of SPIE.