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The combination of optical and mechanical resonances offers strong hybrid nonlinearities, bistability, and the ability to efficiently control the optical response of nanomechanical photonic metamaterials with electric and magnetic field. While optical resonances can be characterized in routine transmission and reflection experiments, mapping the high‐frequency mechanical resonances of complex metamaterial structures is challenging. Here, it is reported that high‐frequency time‐domain fluctuations in the optical transmission and reflection spectra of nanomechanical photonic metamaterials are directly linked to thermal motion of their components and can give information on the fundamental frequencies and damping of the mechanical modes. This is demonstrated by analyzing time‐resolved fluctuations in the transmission and reflection of dielectric and plasmonic nanomembrane metamaterials at room temperature and low ambient gas pressure. These measurements reveal complex mechanical responses, understanding of which is essential for optimization of such functional photonic materials. At room temperature the magnitude of the observed metamaterial transmission and reflection fluctuations is of order 0.1% but may exceed 1% at optical resonances. [ABSTRACT FROM AUTHOR]

Demonstration of a fiber‐integrated non‐volatile reconfigurable metasurface providing high‐contrast group delay dispersion switching functionality is reported, which may be engineered to operate at wavelengths across the near‐infrared (telecoms) band. Light‐induced amorphous‐crystalline phase switching in a chalcogenide (germanium antimony telluride) metasurface, only a fraction of a wavelength thick, fabricated on the end‐facet of a single‐mode optical fiber, enables intensity and phase modulation of the guided wave at metasurface designated bands. Such devices present a range of opportunities in fiberized remotely programmable phase/intensity multiplexing and dynamic dispersion compensation for emerging telecommunications and data storage/processing applications, including in photonic neural network and neuromorphic computing architectures. [ABSTRACT FROM AUTHOR]

One of the main achievements of metamaterials research has been the development of structured matter exhibiting optical magnetism: first, in an array of microwave split-ring resonators and, soon after, in plasmonic and dielectric metamaterials at THz to visible frequencies. We show here that metamaterial structuring is not necessary to achieve optical magnetic response. Indeed, such a response is an essential characteristic of homogeneous dielectric thin films—Fabry–Pérot resonances, for example, depend on interference among electromagnetic multipoles including the magnetic dipole. [ABSTRACT FROM AUTHOR]

Changes in the arrangement of atoms in matter, known as structural phase transitions or phase changes, offer a remarkable range of opportunities in photonics. They are exploited in optical data storage and laser-based manufacturing, and have been explored as underpinning mechanisms for controlling laser dynamics, optical and plasmonic modulation, and low-energy switching in single nanoparticle devices and metamaterials. Comprehensive modeling of phase-change processes in photonics is, however, extremely challenging as it involves a number of entangled processes including atomic/molecular structural change, domain and crystallization dynamics, change of optical properties in inhomogeneous composite media, and the transport and dissipation of heat and light, which happen on time and length scales spanning several orders of magnitude. Here, for the first time, we show that the description of such complex nonlinear optical processes in phase-change materials can be reduced to a cellular automata model. Using the important example of a polymorphic gallium film, we show that a cellular model based on only a few independent and physically-interpretable parameters can reproduce the experimentally measured behaviors of gallium all-optical switches over a wide range of optical excitation regimes. The cellular automata methodology has considerable heuristic value for the study of complex nonlinear optical processes without the need to understand details of atomic dynamics, band structure, and energy conservation at the nanoscale. [ABSTRACT FROM AUTHOR]

One of the most fascinating properties of chiral molecules is their ability to rotate the polarization of light. Since Faraday's experiments in 1845, it has been known that nonreciprocal polarization rotatory power can be induced by a magnetic field. But can reciprocal polarization rotation in chiral molecules be influenced by an electric field? In the 1960s, Aizu and Zheludev introduced the phenomenon of electrogyration. While the linear (Pockels) and quadratic (Kerr) electro‐optical effects describe how an external electric field changes linear birefringence and dichroism, electrogyration describes how a field changes the circular birefringence and dichroism of a medium. Electrogyration is observed in dielectrics, semiconductors, and ferroelectrics, but the effect is small. This work demonstrates a nanostructured photonic metamaterial that exhibits quadratic electrogyration—proportional to the square of the applied electric field—six orders of magnitude stronger than in any natural medium. Giant quadratic electrogyration emerges as electrostatic forces acting against forces of elasticity change the chiral configuration of the metamaterial's nanoscale building blocks and consequently its polarization rotatory power. This observation of giant electrogyration alters the perception of the effect from that of an esoteric phenomenon into a functional part of the electro‐optic toolkit with application potential. [ABSTRACT FROM AUTHOR]

Non-volatile temperature-induced structural phase transitions such as those found in chalcogenide glasses are known to lead to strong changes in optical properties and are widely used in rewritable optical disk technology. Herein, we demonstrate that thermally activated optical memory can be achieved via the nanostructural reconfiguration of a metallic nanowire metamaterial array made from a shape-memory alloy: A nickel-titanium film of nanoscale thickness structured on the subwavelength scale exhibits bistability of its optical properties upon temperature cycling between 30 °C and 210 °C. The structure, comprising an array of NiTi nanowires coated with a thin film of gold to enhance its plasmonic properties, can exist in two non-volatile states presenting an optical reflectivity differential of 12% via nanoscale mutual displacements of alternating nanowires in the structure. Such all-metal shape-memory photonic gratings and metamaterials may find applications in bistable optical devices. [ABSTRACT FROM AUTHOR]

We report on an experimental and computational (multipole decomposition) study of Fano resonance modes in complementary near-IR plasmonic metamaterials. Resonance wavelengths and linewidths can be controlled by changing the symmetry of the unit cell so as to manipulate the balance among multipole contributions. In the present case, geometrically inverting one half of a fourslot (paired asymmetric double bar) unit cell design changes the relative magnitude of magnetic quadrupole and toroidal dipole contributions leading to the enhanced quality factor, figure of merit, and spectral tuning of the plasmonic Fano resonance. [ABSTRACT FROM AUTHOR]

We report on the demonstration of a femtosecond all-optical modulator providing, without nonlinearity and therefore at arbitrarily low intensity, ultrafast light-by-light control. The device engages the coherent interaction of optical waves on a metamaterial nanostructure only 30nm thick to efficiently control absorption of near-infrared (750-1040 nm) femtosecond pulses, providing switching contrast ratios approaching 3:1 with a modulation bandwidth in excess of 2 THz. The functional paradigm illustrated here opens the path to a broad family of meta-devices for ultrafast optical data processing in coherent networks. [ABSTRACT FROM AUTHOR]