Transcript Augustin Jean Fresnel

Augustin Jean Fresnel
“Nature is not embarrassed by difficulties of analysis”
1788-1827
Early Life
Born 10 May 1788 in Broglie, France (one
year before the French Revolution)
His parents were devoted Jansenists
which had an effect on his entire life
Very early on, he wanted to be an
engineer
Schooling
At age 12 Fresnel started school at the
Ecole Centrale in Caen
From 16-18 he studied at the Ecole
Polytechnique in Paris
Then he received 3 years of technical
courses and practical engineering at the
Ecole des Ponts et Chaussees
Career and Later Life
Worked as a civil engineer
Fought against Napolean when he
returned from Elba
Worked for the Lighthouse Commission
and developed Fresnel Lenses
Had poor health most of his life and finally
died of tuberculosis at age 39
Fresnel
Lens
[He saw] the highest merit in personal achievement,
performance of duty, and service to society. Serious,
intent, haunted by thoughts of an early grave, Fresnel
bound himself closely to these ideals, shunning
pleasures and amusements and working to the point of
exhaustion. Despite the urgency of everything he
attempted, Fresnel was always attentive to detail,
systematic, and thorough. In science no less than in
politics he held tenaciously to his convictions and
defended them with courage and vigour. ... he voiced
outrage when the behaviour of others fell short of his
own high ethical standards. At times this approached a
rankling self-righteousness, but generally his
contemporaries saw him as reserved, gentle, and
charitable.
Physics Contributions
Strong Proponent of the wave theory of light
Faced strong opposition to his point of view
Finally turned the tide by winning the Academie
des Sciences Grand Prix of 1819
His showed how to calculate the intensity of light
at every point behind the diffracter using what
we call Fresnel’s integrals
Stated that light is completely transverse waves
Discovered circularly polarized light
Poisson’s Spot
Poisson’s Spot
Bibliography
Biography in Dictionary of Scientific Biography (New
York 1970-1990).
R Baierlein, Newton to Einstein (Cambridge, 1992).
J J O'Connor, E F Robertson, http://www-history.mcs.standrews.ac.uk/Mathematicians/Fresnel.html, School of
Mathematics and Statistics University of St Andrews,
Scotland.
http://lighthousegetaway.com/lights/fresnel.html
In 1822 a French Physicist named Augustin Fresnel invented a lens
that would make his name commonplace along the seacoasts of
Europe and North America. It looked like a giant glass beehive, with
a light at the center. The lens could be as tall as twelve feet, with
concentric rings of glass prisms above and below to bend the light
into a narrow beam. At the center the lens was shaped like a
magnifying glass, so the concentrated beam was even more
powerful. Tests showed that while an open flame lost nearly 97% of
its light, and a flame with reflectors behind it still lost 83% of its light,
the fresnel lens was able to capture all but 17% of its light. Because
of its amazing efficiency, a fresnel lens could easily throw its light 20
or more miles to the horizon. Note the enormous "bulls-eyes" in the
original Cape Canaveral first-order lens, which is on display at
Ponce Inlet, Florida. The bulls-eyes bend the light into a round beam
to create a flashing effect.