Plasmonic nanorings provide the unique advantage of a pronounced plasmonic field enhancement inside their core. If filled with a polarizable medium, it may significantly enhance its optical effects. Here, we demonstrate this proposition by filling gold nanorings with lithium niobate. The generated second harmonic signal is compared to the signal originating from an unpatterned lithium niobate surface. Measurements and simulation confirm an enhancement of about 20. Applications requiring nanoscopic localized light sources like fluorescence spectroscopy or quantum communication will benefit from our findings.

An optically pumped circular grating polymer laser (see Figure) is obtained using a nanostructured quartz substrate covered with a thin film of methyl‐substituted ladder‐type poly(p‐phenylene) (MeLPPP). The second‐order grating serves at the same time as a 2D feedback mechanism and as an output coupler. Laser emission perpendicular to the substrate with a clear threshold behavior, an extremely narrow spectral width, and a highly directional beam is achieved.

We experimentally and numerically study the propagation of light through amorphous metamaterials. For this purpose we introduce a precisely controllable degree of positional disorder into a perfectly periodic system, transforming it to a partially disordered and ultimately an amorphous metamaterial. The observable spectral features occurring upon this transition and the impact of coherent interactions among neighboring unit cells are revealed. Backed by numerical simulations, the effective properties of the metamaterials are retrieved, most notably for the amorphous one. The most important finding with respect to negative index materials is that their magnetic properties are not affected by an arbitrarily high degree of disorder. This work enables the quantitative evaluation of effective properties of amorphous metamaterials fabricated by bottom-up approaches

We demonstrate for the first time a fast and easy nanoimprint lithography (NIL) based stacking process of negative index structures like fishnet and Swiss-cross metamaterials. The process takes a few seconds, is cheap and produces three-dimensional (3D) negative index materials (NIMs) on a large area which is suitable for mass production. It can be performed on all common substrates even on flexible plastic foils. This work is therefore an important step toward novel and breakthrough applications of NIMs such as cloaking devices, perfect lenses and magnification of objects using NIM prisms. The optical properties of the fabricated samples were measured by means of transmission and reflection spectroscopy. From the measured data we retrieved the effective refractive index which is shown to be negative for a wavelength around 1.8 µm for the fishnet metamaterial while the Swiss-cross metamaterial samples show a distinct resonance at wavelength around 1.4 µm.

We present an approach for extremely fast, wafer-scale fabrication of chiral starfish metamaterials based on electron beam- and on-edge lithography. A millimeter sized array of both the planar chiral and the true 3D chiral starfish is realized, and their chiroptical performances are compared by circular dichroism measurements. We find optical activity in the visible and near-infrared spectral range, where the 3D starfish clearly outperforms the planar design by almost 2 orders of magnitude, though fabrication efforts are only moderately increased. The presented approach is capable of bridging the gap between high performance optical chiral metamaterials and industrial production by nanoimprint technology