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Student Process monitoring using photo-acoustic emission in Direct Laser Interference Patterning

Friday (26.06.2020)
11:50 - 12:10 Room 3
Part of:

Due to its flexible applications, functional laser surface texturing using Direct Laser Interference Patterning (DLIP) has developed into a powerful tool to fabricate well-defined micro-textures which mimic natural surfaces, for example the lotus effect for self-cleaning properties or the structure of shark skin for reduced friction. The fabrication of DLIP surface patterns with micro- and submicrometer resolution necessitates advanced monitoring strategies in order to the control the ablation quality as well as to ensure DLIP-pattern repeatability. Additionally, the employed monitoring systems require in-line capabilities to allow for closed-loop approaches. A possible approach, already applied to direct laser writing (DLW) is the use of acoustic emission (AE) generated by the laser-interaction with the surface.


This work describes the pre-processing and analysis of the acoustic information extracted from the AE using an electret microphone during laser-material interaction. The process-inherent characteristics such as the size of the interaction area, the influence of the laser pulse energy and changes in the spatial period during DLIP processing are examined. The results show that the working position of the interference volume, defined as the position between the crossing of the beams and the surface, can be correlated with the amplitude and spectral shape of the AE. This enables to use the proposed approach as an auto-focus method during DLIP processing.

Dipl.-Ing. Tobias Steege
Fraunhofer Institute for Material and Beam Technology IWS Dresden
Additional Authors:
  • Sabri Alamri
    Fraunhofer Institute for Material and Beam Technology IWS Dresden
  • Prof. Dr. Andrés Fabián Lasagni
    Technische Universität Dresden
  • Dr. Tim Kunze
    Fraunhofer Institute for Material and Beam Technology IWS Dresden


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