Fresnel, Augustin Jean 1788-1827, French physicist and engineer. He is known for his research on light, especially on conditions governing interference phenomena in polarized light and on double refraction. His work supported the wave theory of light and the concept of transverse vibrations in light waves, which he analyzed mathematically. He devised a method of producing circularly polarized light and promoted the replacement of mirrors with compound lenses in lighthouses. He served as a government engineer during most of his career.