Micro- and nano structuring by means of laser radiation

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Schematic view on the laser backside etching configuration
Laser-etched fused silica surface
Laser etched spiral phase plate with a PV value of about 1000 nm
Nanostructured fused silica surface by pattern transfer of laser-based fabricated metallic nanostructures

Laser patterning of dielectric materials

This work on the high-quality, low-damage structuring of dielectrics is based on our own fundamental investigations, which aimed to the investigation of the process-determining laser-photon-material interaction processes during the so-called laser etching. Laser etching combines various methods that make laser-induced chemical reactions in the interface region to the substrate (workpiece) usable in order to achieve increased absorption in the interface region of the dielectrics and thus enable precise removal of material at nanometer depth resolution with minimal damage to the dielectric surface. This is often an additional materials used. Laser etching processes allow the production of high-precision optical elements with lateral structures corresponding to the laser spot diameter and a surface roughness of less than 10 nm.
For the direct structuring of optical functional surfaces different processing methods are used. The dimensions of the functional surfaces are limited by the laser spot size and the laser spot grid area. By means of patterned absorber, which is also achievable with laser machining, pattern dimensions below the diffraction limit of the laser radiation used can be achieved. 

Investigated laser etching processes are:

  • LIBWE – laser-induced backside wet etching
  • LIBDE – laser-induced backside dry etching
  • LESAL – laser etching at surface adsorbed layers
  • LIFE – laser-induced front side etching

 

Selected publications

  • P. Lorenz, J. Zajadacz, L. Bayer, M. Ehrhardt, K. Zimmer
    Nanodrilling of fused silica using nanosecond laser radiation

    Applied Surface Science 351 (2015) 935-945
    doi.org/10.1016/j.apsusc.2015.06.041
  • K. Zimmer, M. Ehrhardt, R. Böhme
    Laser-induced backside wet etching: processes, results, and applications

    Laser ablation in liquids - Principles and Applications in the Preparation of Nanomaterials, Guowei Yang (Ed.) (2012) 1013-1132
    ISBN: 978-981-4310-95-6
  • K. Zimmer, R. Böhme
    Precise etching of fused silica for refractive and diffractive micro-optical applications

    Optics and Lasers in Engineering 43 (12) (2005) 1349-1360
    doi.org/10.1016/j.optlaseng.2004.12.003
  • M. Mäder, K. Zimmer, R. Böhme, T. Höche, J. W. Gerlach, B. Rauschenbach
    Nano-Patterning by Diffraction Mask-Projection Laser Ablation

    Journal of Laser Micro/ Nanoengineering 3 (1) (2008) 9-13
    DOI: 10.2961/jlmn.2008.01.0003
  • P. Lorenz, M. Kloeppel, F. Frost, M. Ehrhardt, K. Zimmer, P. Li
    Laser-induced circular nanostructures in fused silica assisted by a self-assembling chromium layer

    Applied Surface Science 280 (2013) 933-939
    doi.org/10.1016/j.apsusc.2013.05.102