The Wave Nature of Light - Sections 24.4 - 24.6

Announcements Review Diffraction by a Single Slit Final QuestionsThe wave theory of light: a historical perspectiveNewton’s view of light – that it consisted of a stream of particles – was the prevailing view in mostscientific circles of the early 19th centuryDuring Newton’s lifetime, however, there was another theory, advanced by the Dutch physicist ChristianHuygens in 1678, that light was a wave (Huygens’ principle)In 1801 – 123 years after Hugyens first proposed that light was a wave – Thomas Young experimentallydemonstrated the wave nature of light (the double slit experiment) by demonstrating interferenceHowever, even with this remarkable demonstration, the scientific community was slow to adopt thewave-theory explanationIn 1819, the French Academy of Sciences organized a competition for an essay on diffraction – AugustinFresnel, a French physicist and supporter of the wave-theory of light, won (Huygens-Fresnel principle)The Academy, however, was unconvinced, with the preeminent French mathematician Siméon Poissonpointing out this “strange result”:If Fresnel’s theories were correct, then light waves should diffractinto the shadow region of a sphere as they pass its edge, producinga bright spot at the center of the shadowHowever, the French physicist and mathematician Dominique Arago soon experimentally verified thisstartling prediction (a Poisson bright spot)The Wave Nature of Light