Oswald Leroy

Oswald Jozef Leroy (born 1936 in Passendale, Belgium, died 7 September 2022) is a Belgian mathematician known for his contributions to theoretical acousto-optics.

In 1991 Leroy was awarded an honorary doctorate from the University of Gdansk, for his contributions to theoretical acousto-optics and to celebrate a collaboration with the team of Antoni Sliwinski [pl] at the Institute of Physics of the University of Gdansk. In 2001 he has received the ‘Médaille étrangère’ of the French Acoustical Society.

Leroy's biggest achievement was a theoretical study of the interaction of light with two adjacent ultrasonic beams under different conditions in terms of beam shape, frequency content and intensity. Understanding of this phenomenon was very important in the 1970s when new acousto-optic devices were developed (mainly due to novel developments in laser technology) that utilized adjacent ultrasonic beams. Such devices were being used in optical modulators, optical scanners, information processing , optical filtering and frequency-spectrum analysis. Before his contribution only the interaction of light with one ultrasonic beam was understood. Since then, acousto-optic devices have been used in telecommunication and military applications.

Leroy received his PhD from Ghent University in the group of Robert A. Mertens for his thesis entitled Diffraction of light by ultrasound. He worked as an assistant professor at Ghent University from 1966 to 1972 and has been a tenured professor at the Catholic University of Leuven since 1972. New developments in laser physics formed the ground for collaborations between the team of Leroy and different other laboratories. He was a guest professor at the Paris Diderot University and Université de Bordeaux, the University of Tennessee and the Tokyo Institute of Technology. Furthermore, he has collaborated with the University of Gdansk, Georgetown University, and the University of Houston. He retired in 2001 and received the title of emeritus professor.