Beam characterization of a materials processing CO{sub 2} laser
- Sandia National Labs., Albuquerque, NM (United States)
Characterization of the propagation and focusing ability of a laser beam is essential in laser materials processing applications. This characterization is of particular importance in processes such as laser drilling and melting of metals. Here, the propagation of focused laser radiation has been characterized for 12 lenses using the laser propagation equation, yielding measurements of beam quality, spot size, and depth of focus. The beam quality of the laser places an intrinsic limit on the minimum focused spot size and was found to be M{sup 2} = 1.5 {+-} 0.09 (M{sup 2} = 1.0 corresponds to an ideal beam) for the 1,200-W CW CO{sub 2} laser used in this study. As the lens focal length was decreased, measured values of spot size and M{sup 2} were significantly increased over the values predicted for aberration-free lenses. This increase is believed to be due to spherical aberration introduced by the lenses. It was also found that at short focal lengths, aspheric lenses produce better results than planoconvex, meniscus, or diffractive lenses, at a laser power of 300 W. Equations were determined that accurately predict beam quality, spot size, and depth of focus under the influence of spherical aberration.
- Research Organization:
- Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 218536
- Journal Information:
- Welding Journal, Vol. 75, Issue 2; Other Information: PBD: Feb 1996
- Country of Publication:
- United States
- Language:
- English
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