numerical aperture

(redirected from Acceptance angle)
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numerical aperture

[nü′mer·i·kəl ′ap·ə·chər]
(optics)
A measure of the resolving power of a microscope objective, equal to the product of the refractive index of the medium in front of the objective and the sine of the angle between the outermost ray entering the objective and the optical axis. Abbreviated N.A.

numerical aperture

The measurement of the acceptance angle of an optical fiber, which is the maximum angle at which the core of the fiber will take in light that will be contained within the core. Taken from the fiber core axis (center of core), the measurement is the square root of the squared refractive index of the core minus the squared refractive index of the cladding. See critical angle and fiber optics glossary.


The Acceptance Angle
The numerical aperture measures the acceptance angle of a fiber.
References in periodicals archive ?
With an acceptance angle of [+ or -] 30 degrees, the probe can measure difficult-to-access features at a scanning speed of 1,000 points per second for rapid throughput.
The fit to the data taken for samples outside the IS above 300 nm provided estimates of the microsphere diameter, real part of the index of refraction, suspension concentration, and the instrument acceptance angle.
The sensor uses wide acceptance angle pixel technology, which helps to ensure minimum module height while maintaining the crucial corner performance.
The sensor's three transmission and receiver units have an acceptance angle of three degrees and, from about 100 yards away, scan the entire width of a three-lane motorway, detecting any vehicles ahead.
Alex Clarke, global alliance manager with Coventry, UK-based OAS said the antenna can provide an acceptance angle of over 25% off center before the connection between devices fails while still achieving considerable performance benefits over current IR technologies.
The detector acceptance angle was set at [similar to] 0.
Due to an acceptance angle of up to 85A and thus more than in conventional materials considerably more light can be absorbed by the fiber and thus transmitted.
The second term was the integral of the L-M differential cross section over the detector acceptance angle.
Couillaud also commented on the technology saying "the combinations of low insertion loss and wide acceptance angle should make the Pico Pass filters easier to integrate and increase system throughput efficiency.
Their output and beam parameters have been closely matched so that the enormously powerful light beam, which leaves the small laser aperture at a defined angle, can be perfectly coupled into a small fiber core diameter with a restricted acceptance angle.