Tunable fishnet metamaterials infiltrated by liquid crystals

We analyze numerically the optical response and effective macroscopic parameters of fishnet metamaterials infiltrated with a nematic liquid crystal. We show that even a small amount of liquid crystal can provide tuning of the structures due to reorientation of the liquid crystal director. This enables switchable optical metamaterials, where the refractive index can be switched from positive to negative by an external field. This tuning is primarily determined by the shift of the cut-off wavelength of the holes, with only a small influence due to the change in plasmon dispersio

Manipulation of Airy surface plasmon beams

We demonstrate experimentally the manipulation of Airy surface plasmon beams in a linear potential. For this purpose, we fabricate dielectric-loaded plasmonic structures with a graded refractive index by negative-tone gray-scale electron beam lithography. Using such carefully engineered potentials, we show that the bending of an Airy surface plasmon beam can be fully reversed by the potential.We acknowledge support from the Australian Research Council and the Australian National Computational Infrastructure

Generation and near-field imaging of Airy surface plasmons

We demonstrate experimentally the generation and near-field imaging of nondiffracting surface waves - plasmonic Airy beams, propagating on the surface of a gold metal film. The Airy plasmons are excited by an engineered nanoscale phase grating, and demonstrate significant beam bending over their propagation. We show that the observed Airy plasmons exhibit self-healing properties, suggesting novel applications in plasmonic circuitry and surface optical manipulation.Comment: 4 pages, 4 figure

Electro-optical switching by liquid-crystal controlled metasurfaces

We study the optical response of a metamaterial surface created by a lattice of split-ring resonators covered with a nematic liquid crystal and demonstrate millisecond timescale switching between electric and magnetic resonances of the metasurface. This is achieved due to a high sensitivity of liquid-crystal molecular reorientation to the symmetry of the metasurface as well as to the presence of a bias electric field. Our experiments are complemented by numerical simulations of the liquid-crystal reorientation.Comment: 6 pages, 3 figure

Modulational instability and solitons in a periodic dissipative feedback system

International audienceWe review our recent experimental results on control of the modulational instability, pattern formation, and solitons in a nonlinear discrete dissipative feedback system. We show that the discreetness and bandgap effects can provide efficient control of the nonlinear instability modes of the system. Furthermore, we explore the possibilities for excitation of dissipative discrete solitons in such system through seeding with a narrow addressing beam

Controlling plasmonic hot spots by interfering Airy beams

We predict and demonstrate the generation of a plasmonic hot spot on the surface of a metal film by the interference of two Airy surface plasmons. We show that the position of the hot spot can be controlled by the distance between the excitation gratings as well as by the phase front of the initial excitation. The observed effect constitutes a planar analogy to Airy beam autofocusing and offers new opportunities for spatially resolved surface plasmon sensing and optical surface tweezers.We acknowledge support from the German Research Foundation [SPP 1391 “Ultrafast Nanooptics” and Jena School for Microbial Communication (JSMC)], the German Federal Ministry of Education and Research (PhoNa), the Thuringian Ministry of Education Science and Culture (MeMa), the Australian Research Council, the Go-8 Australia-Germany (Go8-DAAD) Joint Research Cooperation Scheme, and the Australian National Computational Infrastructure

Multiresponsive Dielectric Metasurfaces Based on Dual Light‐ and Temperature‐Responsive Copolymers

Abstract Tunability is essential for unlocking a range of practical applications of high‐efficiency metasurface‐based nanophotonic devices and systems. Increased research efforts in this area during recent years led to significant progress regarding tuning mechanisms, speed, and diverse active functionalities. However, so far almost all the demonstrated works are based on a single type of physical stimulus, thereby excluding important opportunities to enhance the modulation range of the metadevices, the available design options, as well as interaction channels between the metadevices and their environment. In this article, it is experimentally demonstrated that multi‐responsive metasurfaces can be realized by combining asymmetric, highly resonant metasurfaces with multi‐responsive polymeric materials. The respective copolymers combine light‐ and temperature‐responsive comonomers in an optimized ratio. This work demonstrates clearly reversible light‐responsive, temperature‐responsive, and co‐responsive tuning of the metasurface optical resonance positions at near‐infrared wavelengths, featuring maximum spectral resonance shifts of nearly twice the full‐width‐at‐half‐maximum and accompanied by more than 60% absolute modulation in transmittance. This work provides new design freedom for multifunctional metadevices and can potentially be expanded to other types of copolymers as well. Furthermore, the studied hybrid multiresponsive systems are promising candidates for multi‐dimensional sensing applications.Light and temperature‐responsive polymers are integrated with asymmetric silicon metasurfaces for dual‐responsive tuning of their transmittance. Reversible resonance shifts induced by light exposure, temperature changes or a combination of both stimuli are experimentally demonstrated. This work paves the way for multiresponsive metasurface components and is promising for multi‐dimensional interactive smart optical devices. imag

Liquid crystal based nonlinear fishnet metamaterials

We study experimentally the nonlinear properties of fishnet metamaterials infiltrated with nematic liquid crystals and find that moderate laser powers result in significant changes of the optical transmission of the composite structures. We also show that the nonlinear response of our structure can be further tuned with a bias electric field, enabling the realization of electrically tunable nonlinear metamaterials.We acknowledge the support by the Australian Research Council, the Australian National Computational Infrastructure, and the ACT Node of Australian National Fabrication Facility

Tilted response of fishnet metamaterials at near-infrared optical wavelengths

We study experimentally the transmission properties of Au-TiO2 -Au fishnet metamaterials in the near-infrared spectral range and analyze the change in the transmission resonances at varying angles of incidence and different input polarizations. The results show that the main transmission peak through the fishnet is due to the excitation of hole modes. This high-transmission region is significantly influenced by surface plasmon coupling when the incident electric field has a component normal to the metal plates, while little change with respect to tilt is observed when the electric field is parallel to the two metal films of the fishnet