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Proceedings Paper

Optical alignment of a high-speed rotating dove-prism for dual wavelength use (Conference Presentation)
Author(s): Frank Zibner

Paper Abstract

Helical drilling and helical cutting using a rotating Dove-prism is a highly advanced manufacturing technology for high-precision laser micro processing. This optical approach is often combined with an ultra-short pulsed laser source to enable the process capability of almost all materials due to the vapor dominated ablation process. The optical system shall be designed and coated for the use of multiple wavelengths based on the wavelength- dependent absorption behavior of different materials. The designed length of the Dove-prism is a function of the wavelength. Therefore the use of more than one wavelength results in an average solution. Moreover the manufacturing deviations in length and angle have to be taken into account. The collimated deviations from the ideal state result in a misalignment causing the optical path to take the shape of a Limacon of Pascal. This effect needs to be minimized to a maximum deviation between the two circles of 1µm. Additional optical elements and degrees of freedom in adjusting the position and angle of the dove prism relatively to the rotation axis are needed. To solve this issue the balancing holder has been expanded to hold four optical elements that each can be rotated around an axis that either lies in a horizontal plane or perpendicular to this. The optical elements are fixed after adjustment in a way that they do not perform any movement even under the load of high speed rotation of up to 15.000RPM. This paper will present the adjusting process for three independent systems to show the overall tolerance that is needed to achieve accuracies of at least 1µm.

Paper Details

Date Published: 10 September 2019
Proc. SPIE 11103, Optical Modeling and System Alignment, 1110307 (10 September 2019); doi: 10.1117/12.2525700
Show Author Affiliations
Frank Zibner, Fraunhofer-Institut für Lasertechnik (Germany)

Published in SPIE Proceedings Vol. 11103:
Optical Modeling and System Alignment
Mark A. Kahan; José Sasián; Richard N. Youngworth, Editor(s)

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