Large-area plasmonics and sensors : fabrication of plasmonic nanostructures by laser interference lithography and femtosecond direct laser writing

Abstract

The interaction of light with various types of metallic nanostructures reveals unique optical properties originating from the excitation of the localized surface plasmon resonances, which can be used for a wide range of spectroscopic and sensing applications. While, precisely defined and tailored nanostructures are essential building blocks for realizing such schemes, the commonly used electron-beam lithography is a cost-intensive and time-consuming method to create well-defined nanostructures over small areas. However, a low-cost and high-throughput fabricationmethod over large areas is crucial to advance plasmonic devices towards life science and technological applications. Building on these concepts, this thesis demonstrates the use of versatile large-area fabrication methods such Laser Interference Lithography (LIL) and Direct Laser Writing (DLW) for the fabrication of different plasmonic devices such as perfect absorber sensors and surface enhanced infrared absorption substrates. Both lithographic techniques allow for fast and homogeneous preparation of various nanoantenna geometries. Utilizing different plasmonic geometries, this work pursues laser interference lithography for large-area fabrication of plasmonic perfect absorber chemical sensors to reliably detect very small amounts of hydrogen. Furthermore, both laser interference lithography and direct laser writing allow for the preparation of large-area plasmonics nanoantenna arrays for surface-enhanced infrared spectroscopy, enabling the detection of small amounts of vibrationally active molecules. Additionally, both techniques combined with subsequent etching processes are employed for nanostructuring of so-called alternative plasmonic materials namely titanium nitride. Titanium nitride, known as a refractory plasmonic material, provides plasmonic properties comparable with gold and can sustain at high temperatures as investigated in the thesis.