Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 90: Sensing, Active Structures and other Applications

O 90.11: Talk

Thursday, March 19, 2015, 17:30–17:45, MA 144

Magnesium for UV plasmonics and chemical reaction sensing — •Florian Sterl, Andreas Tittl, Nikolai Strohfeldt, Ramon Walter, and Harald Giessen — 4th Physics Institute and Research Center SCoPE, University of Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany

Plasmonic structures with resonances in the visible and NIR region can be fabricated from various metals and have been investigated extensively. However, fabricating structures with resonances in the blue and UV region presents a much more challenging task. A promising candidate for UV plasmonics is magnesium, with predicted resonances below 350 nm at intensities comparable to those found for silver. For this reason, we fabricated magnesium nanoantennas via colloidal hole-mask etching as well as electron beam lithography and subsequent electron beam physical vapour deposition. The plasmonic behaviour of these structures was investigated via absorption and scattering spectroscopy. Since Mg is a highly reactive metal, it is highly interesting to investigate the plasmonic response to chemical reactions taking place on the particle surface. To do this experimentally, we continuously record the spectrum of Mg particles during exposure to controlled environments with varying atmospheric contaminants. In this way, we are able to monitor, over extended periods of time, the modification of Mg structures due to oxidation, carbonization, water absorption from humid air, and hydrogen uptake. Potential applications of this principle include the plasmonic detection of various atmospheric compounds.