![]() ![]() The effect of diffraction from an opaque object can be seen as interference between different parts of the wave beyond the diffraction object. When two waves combine, their displacements add, causing either a lesser or greater total displacement depending on the phase difference between the two waves. He very heart of the explanation of all diffraction phenomena is interference. ![]() Augustin-Jean Fresnel did more definitive studies and calculations of diffraction, published in 18, and thereby gave great support to the wave theory of light that had been advanced by Christiaan Huygens and reinvigorated by Young, against Newton's particle theory. Explaining his results by interference of the waves emanating from the two different slits, he deduced that light must propagate as waves. In 1803 Thomas Young did his famous experiment observing interference from two closely spaced slits. James Gregory (1638–1675) observed the diffraction patterns caused by a bird feather, which was effectively the first diffraction grating. Isaac Newton studied these effects and attributed them to inflexion of light rays. ![]() The results of Grimaldi's observations were published posthumously in 1665. The effects of diffraction of light were first carefully observed and characterized by Francesco Maria Grimaldi, who also coined the term diffraction, from the Latin diffringere, 'to break into pieces', referring to light breaking up into different directions. Diffraction can also be a concern in some technical applications it sets a fundamental limit to the resolution of a camera, telescope, or microscope. Sound waves can diffract around objects, this is the reason we can still hear someone calling us even if we are hiding behind a tree. Ocean waves diffract around jetties and other obstacles. All these effects are a consequence of the fact that light is a wave.ĭiffraction can occur with any kind of wave. A shadow of a solid object, using light from a compact source, shows small fringes near its edges. Diffraction in the atmosphere by small particles can cause a bright ring to be visible around a bright light source like the sun or the moon. This principle can be extended to engineer a grating with a structure such that it will produce any diffraction pattern desired the hologram on a credit card is an example. The most colorful examples of diffraction are those involving light for example, the closely spaced tracks on a CD or DVD act as a diffraction grating to form the familiar rainbow pattern we see when looking at a disk. The effects of diffraction can be readily seen in everyday life. The complex patterns resulting from the intensity of a diffracted wave are a result of interference between different parts of a wave that traveled to the observer by different paths. While diffraction always occurs when propagating waves encounter obstacles in their paths, its effects are generally most pronounced for waves where the wavelength is on the order of the size of the diffracting objects. As physical objects have wave-like properties, diffraction also occurs with matter and can be studied according to the principles of quantum mechanics. It occurs with any type of wave, including sound waves, water waves, and electromagnetic waves such as visible light, x-rays and radio waves. Diffraction refers to various phenomena associated with the bending of waves when they interact with obstacles in their path. ![]()
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