ISO 11146-1 PDF

ISO. First edition. Lasers and laser-related equipment —. Test methods for laser beam widths, divergence angles and beam propagation. Find the most up-to-date version of ISO at Engineering Purchase your copy of BS EN ISO as a PDF download or hard copy directly from the official BSI Shop. All BSI British Standards.

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The beam diameter or beam width of an electromagnetic beam is the diameter along any specified line that is perpendicular to the beam axis and intersects it. Since beams typically do not have sharp edges, the diameter can be defined in many different ways.

Five definitions of the beam width are in common use: The beam width can be measured in units of length at a particular plane perpendicular to the beam axis, but it can also refer to the angular width, which is the angle subtended by the beam at the source.

The angular width is also called the beam divergence.

Beam diameter is usually used to characterize electromagnetic beams in the optical regime, and occasionally in the microwave regime, that is, cases in which the aperture from which the beam emerges is very large with respect to the wavelength. Beam diameter usually refers to a beam of circular cross section, but not necessarily so. A beam may, for example, have an elliptical cross section, in which case the orientation of the beam diameter must be specified, for example with respect to the major or minor axis of the elliptical cross section.

The term “beam width” may be preferred in applications where the 11164-1 does not have circular symmetry. The angle between the maximum peak 111146-1 radiated power and the first null no power 111146-1 in this direction is called the Rayleigh beamwidth.


Beam diameter – Wikipedia

The simplest way to define the width of a beam is to choose two diametrically opposite points at which the irradiance is a specified fraction of the beam’s peak irradiance, and take the distance between them as a measure of the beam’s width.

This is also called the half-power beam width HPBW. The American National Standard Z This is the beam diameter definition that is used for computing the maximum permissible exposure to a laser beam. If the beam 1116-1 not fill more than a third of the beam profiler’s sensor area, then there will be a significant number of pixels at the edges of the sensor that register a small baseline value the background value.

The baseline is easily measured by recording the average value for each pixel when the sensor is not illuminated. Before the advent of the CCD beam profiler, the beam width was estimated using the knife-edge technique: The measured curve is the integral of the marginal distribution, and starts at the total beam power and decreases monotonically to zero power.

Most CCD beam profiler’s software can compute the knife-edge width numerically. The main drawback of the knife-edge technique is that the measured value is displayed only jso the scanning direction, minimizing the amount of relevant beam information. To overcome this drawback, an innovative technology offered commercially allows multiple directions beam scanning to create an image like beam representation.

BS EN ISO 11146-1:2005

By mechanically moving the knife edge across the beam, the amount of energy impinging the detector area is determined by the obstruction. The profile is then 111461 from the knife-edge velocity and its relation to the detector’s energy reading.

Unlike other systems, a 1116-1 scanning technique uses several different oriented knife-edges to sweep across the beam. By using tomographic reconstruction, mathematical processes reconstruct the laser beam size in different orientations to an image similar to the one produced by CCD cameras.


The main advantage of this scanning method is that it is free from pixel size limitations as in CCD cameras and allows beam reconstructions with wavelengths not usable with existing CCD technology. Reconstruction is possible for beams in deep UV to far IR. The solution for D86 is found by computing the area of increasingly larger iiso around the centroid until the area contains 0. Unlike the previous beam width definitions, the D86 width is not derived from marginal distributions.

The D86 width is often used in oso that are concerned with knowing exactly how much power is in a given area.

For example, applications of high-energy laser weapons and lidars require precise knowledge of how much transmitted power actually illuminates the target.

The definition given before holds for stigmatic circular symmetric beams only. For astigmatic beams, however, a more rigorous definition of the beam width has to be used:. International standard ISO The fraction of total beam power encompassed by the beam width depends on which definition is used.

The width of laser beams can be measured by capturing an image on a cameraor by using a laser beam profiler. Ieo Wikipedia, the free encyclopedia. For cases related to radio antennas, see beamwidth. Full width at half maximum. Radiant Zemax Knowledge Base. Retrieved June 3, Archived from the original pdf on June 4, Retrieved July 2, Intrinsic and geometrical laser beam classification, propagation and details of test methods”.

Stigmatic and simple astigmatic beams. Intrinsic and geometrical laser beam classification, propagation and details of test methods. Retrieved from ” https: Views Read Edit View history. This page was last edited on 18 Decemberat By using this site, you agree to the Terms of Use and Privacy Policy.