The quality of beam produced by a Q-switched Nd:YAG laser was investigated. A photographic technique associated with image processing system was utilized to determine the beam quality. The invisible light was detected using burn paper at various operation voltages of flashlamp driver in the range of 450 V to 900 V. The permanent record of the beam spots were made via a scanner and analyze using raster graphic or bitmap from a Matrox Inspector version 2.1 software. The line profile each of the beam spot produced an absorption spectrum. The amplitude of the spectrum indicates the depthness of the hole created after laser interaction with photographic paper. Meanwhile the width shows the beam size as well as the surface roughness. Thus the beam quality is illustrated by the depthness and the flatness of the beam spot. The flatter the surface the more uniform the laser beam distribution and the deeper the hole the more energetic the laser beam interacted with burn paper
