An optical system in which the resolution is no longer limited by imperfections in the lenses but only by diffraction is said to be diffraction limited. Even if one were able to make a perfect lens, there is still a limit to the resolution of an image created by such a lens. Due to diffraction, the smallest point to which a lens or mirror can focus a beam of light is the size of the Airy disk. The transmission function for a circular aperture is the step function and the for a slit, it is the rectangular function. The most important application of this concept is in cameras, microscopes and telescopes. The appearance of the diffraction pattern is additionally characterized by the sensitivity of the eye or other detector used to observe the pattern. Mathematically, the diffraction pattern is characterized by the wavelength of light illuminating the circular aperture, and the aperture's size. Īiry wrote the first full theoretical treatment explaining the phenomenon (his 1835 "On the Diffraction of an Object-glass with Circular Aperture"). They succeed each other nearly at equal intervals round the central disc. the star is then seen (in favourable circumstances of tranquil atmosphere, uniform temperature, etc.) as a perfectly round, well-defined planetary disc, surrounded by two, three, or more alternately dark and bright rings, which, if examined attentively, are seen to be slightly coloured at their borders. The Fraunhofer diffraction pattern of an obscured circular aperture using the exact analytic solution is given by I ( ) 1 ( 1 2) 2 ( ( 2 J 1 ( D / z) D / z) 2 ( 2 J 1 ( D / z) D / z)) 2 where is the radial distance from the optical axis. The disk and rings phenomenon had been known prior to Airy John Herschel described the appearance of a bright star seen through a telescope under high magnification for an 1828 article on light for the Encyclopedia Metropolitana: Both are named after George Biddell Airy. The diffraction pattern resulting from a uniformly illuminated, circular aperture has a bright central region, known as the Airy disk, which together with the series of concentric rings around is called the Airy pattern. The Airy disk is of importance in physics, optics, and astronomy. In optics, the Airy disk (or Airy disc) and Airy pattern are descriptions of the best- focused spot of light that a perfect lens with a circular aperture can make, limited by the diffraction of light. Journal of Applied Optics,2008,29(4):649-652.Airy disk captured by 2000 mm camera lens at f/25 aperture. Influence of spatial frequency on diffraction efficiency of transmission hologram[J]. Analysis and explanation of self-imaging effect in spatial-frequency domain[J]. Influence of optical element misalignment of beam spread collimation optical system on Gaussian beam propagation and transformation[J]. Analysis and simulation of diffraction imaging[J]. Xi’an: Xi’an Electronic Science and Technology University Press, 2000. SHI Shun-xiang, ZHANG Hai-xing, LIU Jin-song. Simulation and analysis of the rectangular hole diffraction irradiated by a monochromatic point source[J]. Xi’an: Xi’an Electronic Science and Technology University Press, 2004. Translated by YANG Jia-sun.Beijing: Electronics Industry Press, 2005. Fraunhofer diffraction of Gaussian beam by a circular aperture[J]. Analytics for Fresnel diffraction by a circular aperture[J].
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