Siméon Denis PoissonBaron Siméon Denis Poisson FRS FRSE (si.me.ɔ̃ də.ni pwa.sɔ̃; 21 June 1781 – 25 April 1840) was a French mathematician and physicist who worked on statistics, complex analysis, partial differential equations, the calculus of variations, analytical mechanics, electricity and magnetism, thermodynamics, elasticity, and fluid mechanics. Moreover, he predicted the Poisson spot in his attempt to disprove the wave theory of Augustin-Jean Fresnel, which was later confirmed.
Huygens–Fresnel principleThe Huygens–Fresnel principle (named after Dutch physicist Christiaan Huygens and French physicist Augustin-Jean Fresnel) states that every point on a wavefront is itself the source of spherical wavelets, and the secondary wavelets emanating from different points mutually interfere. The sum of these spherical wavelets forms a new wavefront. As such, the Huygens-Fresnel principle is a method of analysis applied to problems of luminous wave propagation both in the far-field limit and in near-field diffraction as well as reflection.
Young's interference experimentYoung's interference experiment, also called Young's double-slit interferometer, was the original version of the modern double-slit experiment, performed at the beginning of the nineteenth century by Thomas Young. This experiment played a major role in the general acceptance of the wave theory of light. In Young's own judgement, this was the most important of his many achievements. During this period, many scientists proposed a wave theory of light based on experimental observations, including Robert Hooke, Christiaan Huygens and Leonhard Euler.
Fresnel numberThe Fresnel number (F), named after the physicist Augustin-Jean Fresnel, is a dimensionless number occurring in optics, in particular in scalar diffraction theory. For an electromagnetic wave passing through an aperture and hitting a screen, the Fresnel number F is defined as where is the characteristic size (e.g. radius) of the aperture is the distance of the screen from the aperture is the incident wavelength.
François AragoDominique François Jean Arago (Domènec Francesc Joan Aragó), known simply as François Arago (fʁɑ̃swa aʁaɡo; Catalan: Francesc Aragó, fɾənˈsɛsk əɾəˈɣo; 26 February 1786 - 2 October 1853), was a French mathematician, physicist, astronomer, freemason, supporter of the Carbonari revolutionaries and politician. Arago was born at Estagel, a small village of 3,000 near Perpignan, in the département of Pyrénées-Orientales, France, where his father held the position of Treasurer of the Mint.
