Hannover 2016 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 9: Photonics II

Q 9.6: Talk

Monday, February 29, 2016, 15:45–16:00, f342

3D SLM-based STED-lithography — •Julian Hering, Erik H. Waller, and Georg von Freymann — Department of Physics and Research Center OPTIMAS, University of Kaiserslautern

3D direct laser writing (DLW) is a commonly used technology for the fabrication of almost arbitrarily polymer structures in a single processing step. As the achievable resolution in standard DLW is diffraction limited, several proposals using superresolution technology have been presented in recent years. One of the most promising is stimulated emission depletion (STED) inspired lithography. Here, using especially shaped phase masks, a second laser beam suppresses the polymerization reaction via stimulated emission. Using spatial light modulators (SLMs) for the writing as well as the depletion laser beam allows for (i) automatically aligning the setup, (ii) correcting aberrations present in the setup, and (iii) varying the phase masks used for the depletion laser to find optimal conditions. We compare doughnut- and bottlebeam-modes realized with the SLMs to theoretical expectations. In writing experiments we observe a reduction of the lateral polymerization line-width of 50% for the doughnut- mode. The bottlebeam-mode results in a reduction of the axial feature size by 56%. Furthermore, we use a numerical algorithm to calculate corresponding phase- and amplitude-patterns for alternative mode patterns: We compare the writing performance of so called multifoci-modes with the results achieved for doughnut and bottlebeam phase masks. Experimentally, the multifoci-modes show at least comparable performance while being conceptually much simpler to realize.