Arkadiusz Jaroslaw Goszczak

Single-Mode to Multi-Mode Crossover in Thin-Load Polymethyl Methacrylate Plasmonic Waveguides

Mode character and mode dispersion of sub-60-nm-thick polymethyl methacrylate dielectric-loaded surface plasmon-polariton waveguides (DLSPPWs) are investigated using photoemission electron microscopy and finite element method simulations. Experiment and simulation show excellent agreement and allow identifying a crossover from single-mode to multi-mode waveguiding as a function of excitation wavelength λ and DLSSPW cross section. Experiment and simulations yield, furthermore, indications for the formation of a surface plasmon-polariton cavity mode in the close vicinity of the waveguides.

Nanoscale concave structures for field enhancement in organic thin films

A promising method for improving light-absorption in thin-film devices is demonstrated via electrode structuring using Anodic Alumina Oxide (AAO) templates. We present nano-scale concave Al structures of controlled dimensions, formed after anodic oxidation of evaporated high purity aluminum (Al) films and alumina etching. We investigate both experimentally and theoretically the field-enhancement supported by these concave nanostructures as a function of their dimensions. For the experimental investigations, a thin layer of organic polymer coating allows the application of a nondestructive laser ablation technique that reveals field-enhancement at the ridges of the Al nanostructures. The experimental results are complemented by finite-difference time-domain (FDTD) simulations, to support and explain the outcome of the laser ablation experiments. Our method is easily up-scalable and lithography-free and allows one to generate nanostructured electrodes that potentially support field-enhancement in organic thin-film devices, e.g., for the use in future energy harvesting applications.