Fluctuations in beam quality (<i>M</i><sup>2</sup>) have been observed on a pulse-to-pulse basis from an industrial Nd:YAG laser. This was achieved with a compact multiplane imaging method incorporating quadratically distorted diffraction gratings, which enabled simultaneous imaging of nine planes on a single CCD array. With this system, we measured across a range of beam qualities with an associated error (in <i>M</i><sup>2</sup> variation) of the order of 0.7%. Application of the system to fiber-optic beam delivery and laser drilling is demonstrated.
© 2004 Optical Society of America
(050.1950) Diffraction and gratings : Diffraction gratings
(050.1970) Diffraction and gratings : Diffractive optics
(110.4190) Imaging systems : Multiple imaging
(140.3070) Lasers and laser optics : Infrared and far-infrared lasers
(140.3390) Lasers and laser optics : Laser materials processing
Robert W. Lambert, Rodolpho Cortés-Martínez, Andrew J. Waddie, Jonathan D. Shephard, Mohammad R. Taghizadeh, Alan H. Greenaway, and Duncan P. Hand, "Compact Optical System for Pulse-to-Pulse Laser Beam Quality Measurement and Applications in Laser Machining," Appl. Opt. 43, 5037-5046 (2004)