12 September 2008 Randomly varying micro-optical elements for the generation of uniform intensity profiles in coherent laser sources
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Abstract
A wide range of lasers from the UV to the IR are selected based on their optical power and spectral characteristics to match the particular absorption behavior for the material to be processed. Periodic microlens arrays are often used as multi-aperture integrators to transform the Gaussian or non-uniform beam profile into a homogenized intensity profile either in 1-D or 2-D distribution. Each microlens element samples the input inhomogeneous beam and spreads it over a given angular distribution. Incoherent beams that are either temporally or spatially incoherent can produce very uniform intensity profiles. However, coherent beams will experience interference effects in the recombination of the beams generated by each individual microlens element. For many applications, for example pulsed laser sources, it is not possible to use a rotating or moving element, such as a rotating diffuser, to circumvent the interferences resulting from the beam coherence. Micro-optical elements comprised of a randomly varying component can be used to help smooth out the interference effects within the far-field intensity profile.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
K. J. Weible, A. Bich, S. Roth, C. Dumouchel, P. Pernet, M. Eisner, R. Völkel, R. Bitterli, T. Scharf, W. Noell, "Randomly varying micro-optical elements for the generation of uniform intensity profiles in coherent laser sources", Proc. SPIE 7062, Laser Beam Shaping IX, 70620R (12 September 2008); doi: 10.1117/12.795926; https://doi.org/10.1117/12.795926
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