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O: Fachverband Oberflächenphysik

O 66: Plasmonics and nanooptics: Applications and other aspects II

O 66.3: Talk

Wednesday, March 14, 2018, 15:30–15:45, MA 041

Large-area, disordered perfect absorber with multiple resonances in the visible and near infrared — •Ramon Walter and Harald Giessen — 4th Physics Institute, University of Stuttgart

Plasmonic devices with a very high absorption over a wide wavelength range, so-called perfect absorbers, have the potential for many applications as light trapping, photo catalysis and as black background for novel displays. Such systems show a very high absorption at their resonance, just by optimizing their impedance to vacuum values.

Such perfect absorbers can be fabricated on large-area scale, with low-cost, and a high throughput by using colloidal lithography, where nanospheres acting a mask for a dry-etching process. Due of the randomize dispersion of our nanostructures the absorption of the system remains very high over a wide range of incident angles, nearly independently of the polarization.

In this work, we investigate the potential of such devices for multiple resonances. Using nanospheres of different sizes should lead to various sizes of nanostructures and consequently to multiple resonances independently of the polarization. We investigate the interaction between two neighboring resonances in materials with different plasmonic characteristics, like e.g. gold or copper as typical plasmonic materials and nickel or palladium as representative *bad* plasmonic materials.

We believe that our investigations can lead to several designs with the potential for many applications. Systems with a high absorption over a width wavelength regime are also possible as reflectors for a narrow spectral area.