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Proceedings Paper

Field mappers for laser material processing
Author(s): Paul Blair; Matthew Currie; Natalia Trela; Howard J. Baker; Eoin Murphy; Duncan Walker; Roy McBride
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Paper Abstract

The native shape of the single-mode laser beam used for high power material processing applications is circular with a Gaussian intensity profile. Manufacturers are now demanding the ability to transform the intensity profile and shape to be compatible with a new generation of advanced processing applications that require much higher precision and control. We describe the design, fabrication and application of a dual-optic, beam-shaping system for single-mode laser sources, that transforms a Gaussian laser beam by remapping – hence field mapping - the intensity profile to create a wide variety of spot shapes including discs, donuts, XY separable and rotationally symmetric. The pair of optics transform the intensity distribution and subsequently flatten the phase of the beam, with spot sizes and depth of focus close to that of a diffraction limited beam. The field mapping approach to beam-shaping is a refractive solution that does not add speckle to the beam, making it ideal for use with single mode laser sources, moving beyond the limits of conventional field mapping in terms of spot size and achievable shapes. We describe a manufacturing process for refractive optics in fused silica that uses a freeform direct-write process that is especially suited for the fabrication of this type of freeform optic. The beam-shaper described above was manufactured in conventional UV-fused silica using this process. The fabrication process generates a smooth surface (<1nm RMS), leading to laser damage thresholds of greater than 100J/cm2, which is well matched to high power laser sources. Experimental verification of the dual-optic filed mapper is presented.

Paper Details

Date Published: 22 April 2016
PDF: 10 pages
Proc. SPIE 9727, Laser Resonators, Microresonators, and Beam Control XVIII, 97270S (22 April 2016); doi: 10.1117/12.2213481
Show Author Affiliations
Paul Blair, PowerPhotonic Ltd. (United Kingdom)
Matthew Currie, PowerPhotonic Ltd. (United Kingdom)
Natalia Trela, PowerPhotonic Ltd. (United Kingdom)
Howard J. Baker, PowerPhotonic Ltd. (United Kingdom)
Eoin Murphy, PowerPhotonic Ltd. (United Kingdom)
Duncan Walker, Walker Optics (United Kingdom)
Roy McBride, PowerPhotonic Ltd. (United Kingdom)

Published in SPIE Proceedings Vol. 9727:
Laser Resonators, Microresonators, and Beam Control XVIII
Alexis V. Kudryashov; Alan H. Paxton; Vladimir S. Ilchenko, Editor(s)

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