8 October 2014 Measuring effective area of spots from pulsed laser beams
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The effective area of a laser spot is an important quantity used to characterize the laser-induced damage threshold of optical materials according to ISO 21254-1:2011 standard. A method for measuring the effective area/diameter of spots from pulsed laser beams using charge-coupled device camera-based beam profilers is presented. Factors affecting the measurement’s accuracy, as the background noise and the size of the summation area, were evaluated using MATLAB®. To minimize the noise contribution, we use an iterative method similar to the one used to measure the second-moment-based spot sizes. We find that the two analyzed components of the background noise, its zero-mean noise and its offset, have an opposite effect on the measurements of the effective area/diameter as compared with the second-moment-based measurements. We prove that there is an upper limit of the relative error of such iterative measurements of effective area, the iteration limit parameter, and that it is a measurable quantity. We measure the effective area/diameter of laser spots with different sizes from a Nd:YAG laser at 1064 nm, 6 ns pulse duration, 10 Hz repetition frequency, and estimate the standard uncertainty of the measurements. Further, we generalize the effective area/diameter concept to include elongated (elliptical/rectangular) spots.
© 2014 Society of Photo-Optical Instrumentation Engineers (SPIE) 0091-3286/2014/$25.00 © 2014 SPIE
Aurel Stratan, Alexandru Zorila, Laurentiu Rusen, and George Nemes "Measuring effective area of spots from pulsed laser beams," Optical Engineering 53(12), 122513 (8 October 2014). https://doi.org/10.1117/1.OE.53.12.122513
Published: 8 October 2014

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