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Proceedings Paper

Spot-size measurements of a focused cw Nd:YAG laser
Author(s): Marcelino Essien; Paul Lee Schanwald; Phillip W. Fuerschbach
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Paper Abstract

The minimum spotsize, beam quality or M2, and strehl ratio of a focused laser beam provide different measures of the performance of the laser/optic system. Focusing lenses typically used to provide irradiances sufficient to cause melting and/or vaporization of metals or ceramics typically exhibit considerable spherical aberration, and thus limit the minimum spotsize attainable for a given lens at a specific laser power. The purpose of this work it to quantify the increase in the minimum spotsize and decrease in strehl ratio of focused materials processing cw Nd:YAG laser caused by (1) laser cavity heating and (2) spherical aberration introduced by the focusing lens. Minimum spotsize was determined by making several measurements of spotsize along the propagation direction using a scanning aperture system, and fitting the data to the laser propagation equation. These measurements were performed for 6 plano-convex lenses of different focal lengths, using laser power ranging from 500 to 1500 watts. A nonlinear variation of spotsize with laser power and with focal length was observed for the lenses and power levels tested.

Paper Details

Date Published: 17 April 1995
PDF: 6 pages
Proc. SPIE 2375, Beam Control, Diagnostics, Standards, and Propagation, (17 April 1995); doi: 10.1117/12.206980
Show Author Affiliations
Marcelino Essien, Sandia National Labs. (United States)
Paul Lee Schanwald, Sandia National Labs. (United States)
Phillip W. Fuerschbach, Sandia National Labs. (United States)


Published in SPIE Proceedings Vol. 2375:
Beam Control, Diagnostics, Standards, and Propagation
Lindsay W. Austin; Adolf Giesen; Daniel H. Leslie, Editor(s)

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