2021, Deinhart, Victor, Kern, Lisa-Marie, Kirchhof, Jan N., Juergensen, Sabrina, Sturm, Joris, Krauss, Enno, Feichtner, Thorsten, Kovalchuk, Sviatoslav, Schneider, Michael, Engel, Dieter, Pfau, Bastian, Hecht, Bert, Bolotin, Kirill I., Reich, Stephanie, Höflich, Katja

Focused beams of helium ions are a powerful tool for high-fidelity machining with spatial precision below 5 nm. Achieving such a high patterning precision over large areas and for different materials in a reproducible manner, however, is not trivial. Here, we introduce the Python toolbox FIB-o-mat for automated pattern creation and optimization, providing full flexibility to accomplish demanding patterning tasks. FIB-o-mat offers high-level pattern creation, enabling high-fidelity large-area patterning and systematic variations in geometry and raster settings. It also offers low-level beam path creation, providing full control over the beam movement and including sophisticated optimization tools. Three applications showcasing the potential of He ion beam nanofabrication for two-dimensional material systems and devices using FIB-o-mat are presented.

2018-10-23, Loiko, Pavel, Bora, Tanujjal, Serres, Josep Maria, Yu, Haohai, Aguiló, Magdalena, Díaz, Francesc, Griebner, Uwe, Petrov, Valentin, Mateos, Xavier, Dutta, Joydeep

Zinc oxide (ZnO) nanorods (NRs) oriented along the crystallographic [001] axis are grown by the hydrothermal method on glass substrates. The ZnO NRs exhibit a broadband (1–2 µm) near-IR absorption ascribed to the singly charged zinc vacancy VZn−1. The saturable absorption of the ZnO NRs is studied at ≈1 µm under picosecond excitation, revealing a low saturation intensity, ≈10 kW/cm2, and high fraction of the saturable losses. The ZnO NRs are applied as saturable absorbers in diode-pumped Yb (≈1.03 µm) and Tm (≈1.94 µm) lasers generating nanosecond pulses. The ZnO NRs grown on various optical surfaces are promising broadband saturable absorbers for nanosecond near-IR lasers in bulk and waveguide geometries.