Numerical Aperture
a measure of the acceptance angle of a lens. Higher numerical aperture means the lens gather more diffraction orders yielding higher resolution but at the expense of depth of focus. | ||||
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Numerical Aperture Definition from Law Dictionaries & Glossaries
| President's DNA Initiative Glossary |
Numerical aperture
A measure of the information-collecting ability of a microscope optic. The greater the NA, the better the resolving ability. It is a measure of the light-gathering capacity of the lens system and determines its resolving power and depth of field.
A measure of the information-collecting ability of a microscope optic. The greater the NA, the better the resolving ability. It is a measure of the light-gathering capacity of the lens system and determines its resolving power and depth of field.
Numerical Aperture Definition from Science & Technology Dictionaries & Glossaries
| Fiber Optics, Optical Networking Terms |
Numerical Aperture
The light-gathering ability of a fiber; the maximum angle to the fiber axis at which light will be accepted and propagated through the fiber. The measure of the lightacceptance angle of an optical fiber. NA = sin x, where x is the acceptance angle. NA is also used to describe the angular spread of light from a central axis, as in exiting a fiber, emitting from a source, or entering a detector
The light-gathering ability of a fiber; the maximum angle to the fiber axis at which light will be accepted and propagated through the fiber. The measure of the lightacceptance angle of an optical fiber. NA = sin x, where x is the acceptance angle. NA is also used to describe the angular spread of light from a central axis, as in exiting a fiber, emitting from a source, or entering a detector
| Telecommunication Standard Terms |
numerical aperture (NA )
1. The sine of the vertex angle of the largest cone of meridional rays that can enter or leave an optical system or element, multiplied by the refractive index of the medium in which the vertex of the cone is located. Note: The NA is generally measured with respect to an object or image point and will vary as that point is moved. 2. For an optical fiber in which the refractive index decreases monotonically from n 1 on the axis to n 2 in the cladding, an expression of the extent of the fiber's ability to accept, in its bound modes, non-normal incident rays, given by NA = (n 12-n 22)½. Note: In multimode fibers, the term equilibrium numerical aperture is sometimes used. This refers to the numerical aperture with respect to the extreme exit angle of a ray emerging from a fiber in which equilibrium mode distribution has been established. (188 ) 3. Colloquially, the sine of the radiation or acceptance angle of an optical fiber, multiplied by the refractive index of the material in contact with the exit or entrance face. Note: This usage is approximate and imprecise, but is often encountered.
1. The sine of the vertex angle of the largest cone of meridional rays that can enter or leave an optical system or element, multiplied by the refractive index of the medium in which the vertex of the cone is located. Note: The NA is generally measured with respect to an object or image point and will vary as that point is moved. 2. For an optical fiber in which the refractive index decreases monotonically from n 1 on the axis to n 2 in the cladding, an expression of the extent of the fiber's ability to accept, in its bound modes, non-normal incident rays, given by NA = (n 12-n 22)½. Note: In multimode fibers, the term equilibrium numerical aperture is sometimes used. This refers to the numerical aperture with respect to the extreme exit angle of a ray emerging from a fiber in which equilibrium mode distribution has been established. (188 ) 3. Colloquially, the sine of the radiation or acceptance angle of an optical fiber, multiplied by the refractive index of the material in contact with the exit or entrance face. Note: This usage is approximate and imprecise, but is often encountered.
Numerical Aperture Definition from Encyclopedia Dictionaries & Glossaries
| Wikipedia English - The Free Encyclopedia |
Numerical aperture
In optics, the numerical aperture (NA) of an optical system is a dimensionless number that characterizes the range of angles over which the system can accept or emit light. The exact definition of the term varies slightly between different areas of optics.
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