ISO , Optics and optical instruments — Lasers and laser-related equipment — Vocabulary and symbols; ISO , Lasers and laser-related equipment. ISO. First edition. Lasers and laser-related equipment —. Test methods for laser beam widths, divergence angles and beam propagation. ISO/TR. First edition. Lasers and laser-related equipment — .. in ISO and ISO are essentially based on (but not.
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Beam diameter usually refers to a beam of circular cross section, but not necessarily so. The baseline is easily measured by recording the average value for each pixel when the sensor is not illuminated. The width of laser beams can be measured by capturing an image on 111446-2 cameraor by using a laser beam profiler. If the beam does not 111146-2 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.
This is also called the half-power beam width HPBW.
Unlike other systems, a unique scanning technique uses several different oriented knife-edges to sweep across the beam. Reconstruction is possible for beams in deep UV to far Ixo.
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. Since beams typically do not have sharp edges, the diameter can be defined in many different ways.
The term “beam width” may be preferred in applications where the beam does not have circular symmetry. International standard ISO Most CCD beam profiler’s software can compute the knife-edge width numerically.
Five definitions of the beam width are in common 111146-2 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 page was last edited on 18 Decemberat Intrinsic and geometrical laser beam classification, propagation and details of test methods”. For example, applications of high-energy laser weapons and lidars require precise knowledge of how ixo transmitted power actually illuminates the target. 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.
Intrinsic and geometrical laser beam classification, propagation and details of test methods. Stigmatic and simple astigmatic beams. The main drawback of the knife-edge technique is that the measured value is displayed only on the scanning direction, minimizing the amount of relevant beam information. The D86 width is often used in applications that are concerned with knowing exactly how much power is in a given area.
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The profile is isl measured from the knife-edge velocity and 11146–2 relation to the detector’s energy reading. Archived from the original pdf on June 4, 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.
The American National Standard Z For astigmatic beams, however, a more rigorous definition of the beam width has to be used:. To overcome this drawback, an innovative technology offered commercially allows multiple directions beam scanning to create an image like beam representation.
Retrieved June 3, Retrieved July 2, This is the beam diameter definition that is used for computing the maximum permissible exposure to a laser beam. The fraction of total beam power encompassed by the beam width depends on which definition is used. Retrieved from ” https: Full width at half maximum.
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The angular width is also called the beam divergence. The measured curve is the integral of the marginal distribution, and starts at the total beam power and decreases monotonically to zero power.
The definition given before holds for stigmatic circular symmetric beams only. By mechanically moving the knife edge across the beam, the amount of energy impinging the detector area is determined by the obstruction. Before the advent of the CCD beam profiler, the beam width was estimated using the knife-edge technique: