Klaus Bade

TL;DR: This work investigated propagation of light through a uniaxial photonic metamaterial composed of three-dimensional gold helices arranged on a two-dimensional square lattice that is scalable to other frequency ranges and can be used as a compact broadband circular polarizer.

Abstract: Metallic helical metamaterials give rise to broadband and scalable chiro-optical effects orders of magnitude higher than found in nature. While arrays of gold helices have been suggested as compact circular polarizers, where a large difference of the diagonal elements of the Jones transmission matrix is desired, chiral metamaterials can also be designed to exhibit strong circular-polarization conversions. Here, a novel helical metamaterial design, exhibiting asymmetric, broadband circular-polarization conversion, is introduced. The metamaterial is composed of unit cells with a single helix that changes its handedness halfway along the helix axis. Based on numerical calculations, an intuitive model explaining the principle of operation is given. Furthermore, a novel fabrication approach employing STED-inspired direct laser writing in combination with electrochemical deposition of gold is presented. The experimental data show circular-polarization conversion of up to 75% for an unmatched bandwidth of one octave, in very good agreement with theory.

TL;DR: In this article, the microstructure and micro-hardness of LIGA Ni-W layers and micro testing samples with different compositions (15 and 5 at% W) were electrodeposited.

TL;DR: In this paper, the high cycle fatigue response of electrodeposited LIGA Ni structures was determined using cyclic loading and fractography, and the fatigue behavior was found to be comparable to literature values for conventionally processed bulk Ni.

TL;DR: The thermal stability and mechanical behavior of LIGA Ni-W alloys with 5 and 15% W were investigated in this paper, where the strength of these alloys exceeds that of pure LIGAs and the underlying microstructures of the Ni-w alloys are stable to 700°C.