Augustin-Jean Fresnel was a French civil engineer and physicist whose research in optics led to the almost unanimous acceptance of the wave theory of light, excluding any remnant of Newton’s corpuscular theory, from the late 1830s until the end of the 19th century.
Augustin-Jean Fresnel, French physicist who pioneered in optics and did much to establish the wave theory of light advanced by English physicist Thomas Young. Beginning in 1804 Fresnel served as an engineer building roads in various departments of France. He began his research in optics in 1814. In 1802 Young showed that an interference pattern is produced when light from two sources overlaps, which could happen only if light was a wave. Fresnel’s experiments with various devices for producing interference fringes and diffraction convinced him that the wave theory of light was correct. /
Fresnel presented his work on diffraction as an entry to a competition on the subject sponsored by the French Academy of Sciences in 1819. An experiment was subsequently performed by the French physicist François Arago, and the spot (subsequently called Poisson’s spot) was seen, vindicating Fresnel, who won the competition. Beginning in 1816 Fresnel and Arago studied the laws of the interference of polarized light and were the first to obtain circularly polarized light. This discovery led him to the conclusion that light was not a longitudinal wave, but a transverse wave.
On the recommendation of Arago, in 1819 Fresnel joined Arago on a government committee to improve French lighthouses. In 1821 he produced his first apparatus using the refracting properties of glass, now known as the dioptric system. With a number of lens panels rotating around the lamp, Fresnel was then able in 1824 to produce several revolving beams from a single light source, an improvement over the mirror that produces only a single beam. To collect more of the light wasted vertically, he added above and below the main lens triangular prism sections that both refracted and reflected the light.
Although his work in optics received scant public recognition during his lifetime, Fresnel maintained that not even acclaim from distinguished colleagues could compare with the pleasure of discovering a theoretical truth or confirming a calculation experimentally.