OSA Honorary Member Robert Gaston André Maréchal was born 10 December 1916 in La Garenne, France. Maréchal graduated from the Ecole Normale Superieure in 1941, and received an engineering degree from the Ecole Superieure d’Optique in 1943. He was a lecturer and professor at the Sorbonne and later the Institute of Optics in Orsay.  Maréchal became director of research in the French Ministry of Education, and then general director of the Institut d’optique theorique et appliquee and the Ecole superieure d’optique from 1968 to 1983.

Maréchal was well known for his early work on the combined effects of diffraction and aberration. His research led him to formulate the “Maréchal criterion,” a condition for the maximal intensity to deviate from the absolute maximum obtained at the centre of an Airy spot by less than 20%.

Maréchal served as president of the International Commission for Optics from 1962 to 1966, honorary vice president of the Comité franҫais de physique, and was a founding member of the Franco-Finnish Association for Scientific and Technical Research. He was a member of the French Academy of Sciences and of the French Academy of Technologies.

In 1986, he was named an Honorary Member of the Optical Society in recognition of his preeminent service in the advancement of optics. Additionally, he was elected Fellow and received the C.E.K. Mees Medal from OSA.