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  2. Corrective lens - Wikipedia

    en.wikipedia.org/wiki/Corrective_lens

    Lens materials are classified by their refractive index, as follows: Normal index: 1.48 ≤ n d < 1.54; Mid-index: 1.54 ≤ n d < 1.60; High-index: 1.60 ≤ n d < 1.74; Very high index: 1.76 ≤ n d; This is a general classification. Often for marketing purposes, materials with n d values that are at or above 1.60 can be referred to as "high ...

  3. List of refractive indices - Wikipedia

    en.wikipedia.org/wiki/List_of_refractive_indices

    Standard refractive index measurements are taken at the "yellow doublet" sodium D line, with a wavelength (λ) of 589 nanometers. There are also weaker dependencies on temperature , pressure / stress , etc., as well on precise material compositions (presence of dopants , etc.); for many materials and typical conditions, however, these ...

  4. Gradient-index optics - Wikipedia

    en.wikipedia.org/wiki/Gradient-index_optics

    Gradient-index ( GRIN) optics is the branch of optics covering optical effects produced by a gradient of the refractive index of a material. Such gradual variation can be used to produce lenses with flat surfaces, or lenses that do not have the aberrations typical of traditional spherical lenses. Gradient-index lenses may have a refraction ...

  5. Lidar - Wikipedia

    en.wikipedia.org/wiki/Lidar

    Lidar ( / ˈlaɪdɑːr /, also LIDAR, LiDAR or LADAR, an acronym of "light detection and ranging" [ 1 ] or "laser imaging, detection, and ranging" [ 2 ]) is a method for determining ranges by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver.

  6. High-refractive-index polymer - Wikipedia

    en.wikipedia.org/wiki/High-refractive-index_polymer

    A high-refractive-index polymer (HRIP) is a polymer that has a refractive index greater than 1.50. [1] Such materials are required for anti-reflective coating and photonic devices such as light emitting diodes (LEDs) and image sensors. [1] [2] [3] The refractive index of a polymer is based on several factors which include polarizability, chain ...

  7. Refractive index - Wikipedia

    en.wikipedia.org/wiki/Refractive_index

    A gradient-index lens with a parabolic variation of refractive index (n) with radial distance (x). The lens focuses light in the same way as a conventional lens. If the refractive index of a medium is not constant but varies gradually with the position, the material is known as a gradient-index (GRIN) medium and is described by gradient index ...

  8. Superlens - Wikipedia

    en.wikipedia.org/wiki/Superlens

    A superlens, or super lens, is a lens which uses metamaterials to go beyond the diffraction limit. The diffraction limit is a feature of conventional lenses and microscopes that limits the fineness of their resolution depending on the illumination wavelength and the numerical aperture (NA) of the objective lens.

  9. Fisheye lens - Wikipedia

    en.wikipedia.org/wiki/Fisheye_lens

    A fisheye lens is an ultra wide-angle lens that produces strong visual distortion intended to create a wide panoramic or hemispherical image. [ 4][ 5]: 145 Fisheye lenses achieve extremely wide angles of view, well beyond any rectilinear lens. Instead of producing images with straight lines of perspective ( rectilinear images ), fisheye lenses ...