Everything about Augustin Fresnel totally explained
Augustin-Jean Fresnel (
fray-NELL in English, ] in
French) (
May 10,
1788 –
July 14,
1827), was a
French physicist who contributed significantly to the establishment of the theory of
wave optics. Fresnel studied the behaviour of light both theoretically and experimentally.
Biography
Fresnel was the son of an architect, born at
Broglie (
Eure). His early progress in learning was slow, and he still couldn't read when he was eight years old. At thirteen he entered the École Centrale in
Caen, and at sixteen and a half the
École Polytechnique, where he acquitted himself with distinction. From there he went to the
École des Ponts et Chaussées. He served as an engineer successively in the departments of
Vendée,
Drôme and
Ille-et-Vilaine; but having supported the
Bourbons in 1814 he lost his appointment on
Napoleon's return to power.
On the second restoration of the monarchy, he obtained a post as engineer in
Paris, where much of his life from that time was spent. His researches in optics, continued until his death, appear to have begun about the year 1814, when he prepared a paper on the
aberration of light, which, however, wasn't published. In 1818 he wrote a memoir on
diffraction for which in the ensuing year he received the prize of the
Académie des Sciences at Paris. He was in 1823 unanimously elected a member of the academy, and in 1825 he became a member of the
Royal Society of London, which in 1827, at the time of his last illness, awarded him the
Rumford Medal. In 1819 he was nominated a commissioner of
lighthouses, for which he was the first to construct a special type of lens, now called a
Fresnel lens, as substitutes for mirrors. He died of
tuberculosis at
Ville-d'Avray, near Paris.
His labours in the cause of optical science received during his lifetime only scant public recognition, and some of his papers were not printed by the Académie des Sciences till many years after his death. But as he wrote to Young in 1824: in himself "that sensibility, or that vanity, which people call love of glory" had been blunted. "All the compliments," he says, "that I've received from
Arago,
Laplace and
Biot never gave me so much pleasure as the discovery of a theoretic truth, or the confirmation of a calculation by experiment."
Research
His discoveries and mathematical deductions, building on experimental work by
Thomas Young, extended the
wave theory of
light to a large class of
optical phenomena. In 1817, Young had proposed a small transverse component to light, while yet retaining a far larger longitudinal component. Fresnel, by the year 1821, was able to show via mathematical methods that polarization could be explained only if light was
entirely transverse, with no longitudinal vibration whatsoever.
His use of two plane mirrors of metal, forming with each other an angle of nearly 180°, allowed him to avoid the diffraction effects caused (by the apertures) in the experiment of
F. M. Grimaldi on
interference. This allowed him to conclusively account for the phenomenon of interference in accordance with the wave theory.
With
François Arago he studied the laws of the interference of
polarized rays. He obtained circularly polarized light by means of a rhombus of glass, known as a
Fresnel rhomb, having obtuse angles of 126° and acute angles of 54°.
He is perhaps best known as the inventor of the
Fresnel lens, first adopted in
lighthouses while he was a French commissioner of lighthouses, and found in many applications today.
Further Information
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