Airyschijf

The Airyschijf, also known as the Airy disk, is the central bright spot in the diffraction pattern produced when light passes through a circular aperture. This phenomenon is a fundamental concept in optics and is directly related to the wave nature of light. When light waves encounter an obstacle or opening, they spread out, a process called diffraction. In the case of a circular aperture, the resulting diffraction pattern is not a sharp point but rather a series of concentric bright and dark rings, with the brightest and largest ring being the Airy disk itself.

The size of the Airy disk is inversely proportional to the size of the aperture. A smaller aperture produces a larger Airy disk, while a larger aperture results in a smaller Airy disk. This relationship is quantified by the Rayleigh criterion, which states that two point sources of light are just resolvable when the center of the diffraction pattern of one is directly over the first minimum of the diffraction pattern of the other. This means that the smaller the Airy disk, the better the resolving power of an optical instrument.

The Airy disk is a critical consideration in the design and performance of telescopes, microscopes, and other optical instruments. Its size limits the ability of these instruments to distinguish between closely spaced objects. Understanding and minimizing the Airy disk is essential for achieving high-resolution imaging. The concept was first described by the British astronomer Sir George Biddell Airy in the 19th century.