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Numerical aperture - General optics | A Wisdom Archive on Numerical aperture - General optics | | Numerical aperture - General optics A selection of articles related to Numerical aperture - General optics | |
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Numerical aperture, Numerical aperture - Fiber optics, Numerical aperture - General optics, Numerical aperture - Laser physics, Numerical aperture - Sources, f-number
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ARTICLES RELATED TO Numerical aperture - General optics | | | |  Numerical aperture - General optics: Encyclopedia II - Numerical aperture - General opticsIn most areas of optics, and especially in microscopy, the numerical aperture of an optical system such as an objective lens is defined by
where n is the index of refraction of the medium in which the lens is working (1.0 for air, 1.33 for pure water, and up to 1.56 for oils), and θ is the half-angle of the maximum cone of light that can enter or exit the lens. In general, this is the angle of the real marginal ray in the system. The angular aperture of the lens is twice this value. The NA is generally measured with respect to a particular object ...
See also:Numerical aperture, Numerical aperture - General optics, Numerical aperture - Laser physics, Numerical aperture - Fiber optics, Numerical aperture - Sources Read more here: » Numerical aperture: Encyclopedia II - Numerical aperture - General optics |
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| | | | Numerical aperture - General optics: Encyclopedia II - Numerical aperture - Fiber optics Multimode optical fiber will only propagate light that enters the fiber within a certain cone, known as the acceptance cone of the fiber. The half-angle of this cone is called the acceptance angle, θmax. For step-index multimode fiber, the acceptance angle is determined only by the indexes of refraction:
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where nf is the refractive index of the fiber core, and nc is the refractive index of the cladding.
This has the same form as the numerical aperture in other optical systems, so it has become common to define the ...
See also:Numerical aperture, Numerical aperture - General optics, Numerical aperture - Laser physics, Numerical aperture - Fiber optics, Numerical aperture - Sources Read more here: » Numerical aperture: Encyclopedia II - Numerical aperture - Fiber optics |
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| | | | Numerical aperture - General optics: Encyclopedia II - Numerical aperture - Laser physics In laser physics, the numerical aperture is defined slightly differently. Laser beams spread out as they propagate, but slowly. Far away from the narrowest part of the beam, the spread is roughly linear with distance—the laser beam forms a cone of light in the "far field". The same relation gives the NA,
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but θ is defined differently. Laser beams typically do not have sharp edges like the cone of light that passes through the aperture of a lens does. Instead, the irradiance falls off gradually away from ...
See also:Numerical aperture, Numerical aperture - General optics, Numerical aperture - Laser physics, Numerical aperture - Fiber optics, Numerical aperture - Sources Read more here: » Numerical aperture: Encyclopedia II - Numerical aperture - Laser physics |
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