20 November 1996 Moment characterization of the position stability of laser beams
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Proceedings Volume 2870, Third International Workshop on Laser Beam and Optics Characterization; (1996) https://doi.org/10.1117/12.259899
Event: Third International Workshop on Laser Beam and Optics Characterization, 1996, Quebec City, Canada
Abstract
Laser beam profile measurements always involve integration of the incoming intensity profile over a finite time interval. Under this condition, the measured moments of the spatial profile of a time-varying laser beam are shown to follow the simple algebraic laws of propagation obeyed by the moments of the intensity profile of a purely monochromatic laser field. Transverse shifts of the intensity profile and angular tilts of the axis of propagation of a wandering beam, expressed as fluctuations of the first order moments of the beam, obey similar laws of propagation. The time-variance of first order moments actually propagate the same way as do second order moments. The moment approach thus provides a consistent description of the propagation of a wandering laser beam. Invariants can be defined to quantify the extent of the wandering, taking into account both transverse shifts and angular tilts. It is also possible to define a time-integrated M2 factor, obtained by measuring the second order moments of the time- integrated fluence profile of a laser beam. The increase of this factor, as a function of the time of integration, provides a sense of the time scale and amplitude of the beam wandering.
© (1996) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Michel Morin, Michel Morin, Marc Levesque, Marc Levesque, Alain Mailloux, Alain Mailloux, Pierre Galarneau, Pierre Galarneau, } "Moment characterization of the position stability of laser beams", Proc. SPIE 2870, Third International Workshop on Laser Beam and Optics Characterization, (20 November 1996); doi: 10.1117/12.259899; https://doi.org/10.1117/12.259899
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