Search

Understanding the mechanisms and controlling the possibilities of surface nanostructuring is of crucial interest for both fundamental science and application perspectives. Here, we report a direct experimental observation of laser-induced periodic surface structures (LIPSS) formed near a predesigned gold step edge following single-pulse femtosecond laser irradiation. Simulation results based on a hybrid atomistic-continuum model fully support the experimental observations. We experimentally detect nanosized surface features with a periodicity of ∼300 nm and heights of a few tens of nanometers. We identify two key components of single-pulse LIPSS formation: excitation of surface plasmon polaritons and material reorganization. Our results lay a solid foundation toward simple and efficient usage of light for innovative material processing technologies.

A method for enhancing the photoluminescence of silicon nanocrystals in a silicon oxide matrix by fabrication of periodic surface structures through laser irradiation is demonstrated. ArF excimer lasers are used to produce periodic line structures by material ablation. Photoluminescence, Raman, and transmission electron microscope measurements consistently show the formation of crystalline silicon after high-temperature annealing. A 2.6-fold enhancement of photoluminescence signal is measured for a periodic line structure with 600 nm period. The influence of a surface structure on the photoluminescence from the silicon oxide layer is discussed in terms of a simple model describing the main effect. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms and controlling the possibilities of surface nanostructuring is of crucial interest for both fundamental science and application perspectives. Here, we report a direct experimental observation of laser-induced periodic surface structures (LIPSS) formed near a predesigned gold step edge following single-pulse femtosecond laser irradiation. Simulation results based on a hybrid atomistic-continuum model fully support the experimental observations. We experimentally detect nanosized surface features with a periodicity of ∼300 nm and heights of a few tens of nanometers. We identify two key components of single-pulse LIPSS formation: excitation of surface plasmon polaritons and material reorganization. Our results lay a solid foundation toward simple and efficient usage of light for innovative material processing technologies. [ABSTRACT FROM AUTHOR]

UV-absorbing silicon suboxide (SiOx, x≈1) films can be patterned by excimer laser ablation and subsequently oxidized to fused silica by thermal annealing. This two-step process allows for the fabrication of microstructured components made entirely of fused silica. For example, diffractive optical elements with two phase-quantized levels (binary DOEs) can be produced via structured rear-side ablation of a thin film of silicon suboxide on a fused silica substrate followed by oxidation. Such phase elements can be used as projection masks for precise laser microfabrication, e.g. for parallel nano hole drilling. In addition to these binary patterns, multilevel phase structures are produced by repeating the ablation step after recoating the structured surface with additional layers of silicon suboxide. A diffractive phase element in form of a three-level line grating exhibits a diffraction efficiency of more than 60% in the +1st order. This efficiency can be enhanced by increasing the number of recoating and ablation steps and, thus, the number of phase levels. Within the levels, a surface roughness of Ra ≈ 3 nm is obtained. [ABSTRACT FROM AUTHOR]