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  2. Diffraction-limited system - Wikipedia

    en.wikipedia.org/wiki/Diffraction-limited_system

    Memorial in Jena, Germany to Ernst Karl Abbe, who approximated the diffraction limit of a microscope as = ⁡, where d is the resolvable feature size, λ is the wavelength of light, n is the index of refraction of the medium being imaged in, and θ (depicted as α in the inscription) is the half-angle subtended by the optical objective lens (representing the numerical aperture).

  3. Near-field scanning optical microscope - Wikipedia

    en.wikipedia.org/wiki/Near-field_scanning...

    According to Abbe's theory of image formation, developed in 1873, the resolving capability of an optical component is ultimately limited by the spreading out of each image point due to diffraction. Unless the aperture of the optical component is large enough to collect all the diffracted light, the finer aspects of the image will not correspond ...

  4. Chart of accounts - Wikipedia

    en.wikipedia.org/wiki/Chart_of_accounts

    A chart of accounts (COA) is a list of financial accounts and reference numbers, grouped into categories, such as assets, liabilities, equity, revenue and expenses, and used for recording transactions in the organization's general ledger. Accounts may be associated with an identifier (account number) and a caption or header and are coded by ...

  5. Abbe number - Wikipedia

    en.wikipedia.org/wiki/Abbe_number

    For example, the higher dispersion flint glasses have relatively small Abbe numbers < whereas the lower dispersion crown glasses have larger Abbe numbers. Values of V d {\displaystyle V_{\mathsf {d}}} range from below 25 for very dense flint glasses, around 34 for polycarbonate plastics, up to 65 for common crown glasses, and 75 to 85 for some ...

  6. Optical aberration - Wikipedia

    en.wikipedia.org/wiki/Optical_aberration

    1: Imaging by a lens with chromatic aberration. 2: A lens with less chromatic aberration. In optics, aberration is a property of optical systems, such as lenses and mirrors, that causes the image created by the optical system to not be a faithful reproduction of the object being observed. Aberrations cause the image formed by a lens to be ...

  7. Abbe sine condition - Wikipedia

    en.wikipedia.org/wiki/Abbe_sine_condition

    When the imaging system obeys the Abbe sine condition, the ratio of the sines of these angles equal the (lateral absolute) magnification of the system. In optics , the Abbe sine condition is a condition that must be fulfilled by a lens or other optical system in order for it to produce sharp images of off-axis as well as on-axis objects.

  8. Optical transfer function - Wikipedia

    en.wikipedia.org/wiki/Optical_transfer_function

    Transfer function and example image of an ideal, optical-aberration-free (diffraction-limited) imaging system. It can be read from the plot that the contrast gradually reduces and reaches zero at the spatial frequency of 500 cycles per millimeter, in other words the optical resolution of the image projection is 1/500 th of a millimeter, or 2 ...

  9. Ernst Abbe - Wikipedia

    en.wikipedia.org/wiki/Ernst_Abbe

    In Abbe's 1874 paper, titled "A Contribution to the Theory of the Microscope and the nature of Microscopic Vision", [12] Abbe states that the resolution of a microscope is inversely dependent on its aperture, but without proposing a formula for the resolution limit of a microscope.