Fabrication of inclined non-symmetrical periodic micro-structures using Direct Laser Interference Patterning

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Sabri Alamri - , Fraunhofer Institute for Material and Beam Technology (Author)
  • Mikhael El-Khoury - , Fraunhofer Institute for Material and Beam Technology (Author)
  • Alfredo I Aguilar-Morales - , Fraunhofer Institute for Material and Beam Technology (Author)
  • Sebastian Storm - , Fraunhofer Institute for Material and Beam Technology, TUD Dresden University of Technology (Author)
  • Tim Kunze - , Fraunhofer Institute for Material and Beam Technology (Author)
  • Andrés F Lasagni - , Chair of Laser-based Manufacturing, Fraunhofer Institute for Material and Beam Technology (Author)

Abstract

The direct fabrication of microstructures, having a non-symmetrical morphology with controllable inclination, presents nowadays a challenging task. Natural examples of surfaces with inclined topographies have shown to provide anisotropic functionalities, which have attracted the interest of several researchers in the last years. This work presents a microfabrication technique for producing microstructures with a determined and controllable inclination angle using two-beam Direct Laser Interference Patterning. Polyimide foils are irradiated with a 4 ns UV (266 nm) laser source producing line-like structures with a period varying from 4.6 µm to 16.5 µm. The inclinations, retrieved by tilting the sample with respect to the optical axis of the setup, are changed from 0° to 75°, introducing a well controllable and defined inclination of the structure walls. The structuring parameters (laser fluence, number of laser pulses and interference period) as well as the inclination of the microstructures are correlated with the global tilting of the sample. As a result, a determined laser fluence and number of pulses are necessary to observe a remarkable non-symmetrical morphology of the structures. In addition, the presence of structural undercuts is reported, which opens the possibility for developing new direction-dependent properties on polymeric materials. As an example, preliminary results on light diffraction are presented, showing a similar behavior as blazed diffraction gratings.

Details

Original languageEnglish
Article number5455
JournalScientific reports
Volume9
Issue number1
Publication statusPublished - 1 Apr 2019
Peer-reviewedYes

External IDs

PubMedCentral PMC6443938
Scopus 85063746458

Keywords