Laser beam focal spot analysis

Different types of scanners are used now for direct laser beam focal spot measurements: direct with rotated needle and a pinhole and line scanners, as moving slits, knife-edges, and by moving thin wires. With slits and other types of one-dimensional scanners only projections of intensity distributions can be obtained. Threshold for slits is one of the highest. The other way is scanning of a beam by a thin wire when a bolometric signal is measured.