Augustin Jean Fresnel “Nature is not embarrassed by difficulties of analysis”

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 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. [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

Bibliography Biography in Dictionary of Scientific Biography (New York ). R Baierlein, Newton to Einstein (Cambridge, 1992). J J O'Connor, E F Robertson, andrews.ac.uk/Mathematicians/Fresnel.html, School of Mathematics and Statistics University of St Andrews, Scotland. andrews.ac.uk/Mathematicians/Fresnel.htmlhttp://www-history.mcs.st- andrews.ac.uk/Mathematicians/Fresnel.htmlhttp://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.