Augustin Jean Fresnel

Born May 10, 1788, in Broglie; died July 14, 1827, in Ville-d’Avray, near Paris. French physicist; one of the founders of wave optics. Member of the Paris Academy of Sciences (from 1823).

Fresnel came from a family of architects. He graduated from the Ecole Polytechnique (1806) and the Ecole des Ponts et Chaussées (1809) in Paris. He then obtained a position as a highway engineer. During the Hundred Days, he was involved in military operations against Napoleon, for which he was suspended from his position. Fresnel’s first serious works in optics date to this period. At the end of 1815, he was reinstated in his position, and in 1818, upon the intervention of D.-F. Arago and P. S. Laplace, he was transferred to Paris, where he became involved in the reorganization of lighthouses, proposing a fundamentally new means of lighthouse illumination (the Fresnel lens).

From 1815 to 1823, Fresnel conducted classical studies in the diffraction and polarization of light. He created a theory of diffraction, independently of T. Young, by combining Huygens’ principle and his fundamental idea of the interference of elementary waves (seeHUYGENS-FRESNEL PRINCIPLE). On the basis of his new principle, he explained the laws of geometric optics, in particular, the rectilinear nature of the propagation of light. He devised an approximate method of calculating a diffraction pattern based on the division of a wave front into zones (the Fresnel zones) and was the first to study the diffraction from the edge of a screen and a circular aperture. He devised experiments with bi-mirrors (1816) and biprisms (1819) that became classical examples of interference phenomena (see).

Fresnel was the first to explain polarization phenomena by proceeding from the basic assumption that light waves are transverse (1818; independently of Young), and he established quantitative laws for the polarization phenomena of light during reflection and refraction (Fresnel equation, 1823). His ideas regarding the immobility of the ether and the drag coefficient of light waves laid the foundations for the electrodynamics of moving media of H. A. Lorentz.

Fresnel was a fellow of the Royal Society of London (from 1825).