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We demonstrate metrology and odometry (detection of change in position over time) with resolution in the nanometric - picometric scales by analyzing electrons or topologically structured light scattered from the nanostructures using artificial intelligence. We show how these techniques can be applied to characterization and optimization of nano-opto-mechanical metamaterials and the fundamental studies of dynamics of thermal motion and the physics of phonons in photonic nanostructures.

We report on recent advances in applications of deep learning and topologically structured light to far-field non-destructive imaging with deep subwalength resolution and picometric metrology.

Artificial intelligence (AI) is the most important new methodology in scientific research since adoption of quantum mechanics and it is providing exciting results in multiple fields of science and technology. In this review we summarize research and discuss future opportunities for AI in the domains of photonics, nanophotonics, plasmonics and photonic materials discovery including metamaterials

The building blocks of nanomechanical photonic metamaterials are perturbed by collisions with atoms of ambient atmospheric gas and by phonons in the crystal lattice of the constituent materials. Between collisions movements are ballistic, becoming diffusive (Brownian) at longer time scales. We show how one may distinguish between these regimes using ultrafast hyperspectral SEM nanomotion imaging and discuss their manifestation in the time-dependent optical properties of the metasurfaces.

Wereview the exceptional variety of functionalities accessible by design in nanomechanical photonic metamaterials, whereindynamic reconfiguration of sub-wavelength structure by external stimuli can yield extreme and unusual electro-, magneto-, thermo-, acousto-and nonlinear optical response characteristics.

We report on the manifestation of transmission asymmetry in nano-opto-mechanically reconfigurable all-dielectric metamaterials.The reversible structural reconfiguration of photonic metamaterials manufactured on free-standing elastic nano-membranes, under the action of external stimuli, can drive modulation of their optical properties at high (up to GHz) frequencies. Such nano-mechanical metamaterials can be engineered to present substantive electro-, magneto- and acousto-optic switching coefficients; to manifest large effective optical nonlinearities and bistability; and to enable the interrogation and exploitation of optical phenomena that are extremely small, or indeed non-existent, in bulk media.Resonantly enhanced optical forces generated among the component parts of a free-standing photonic metamaterial can be of comparable magnitude to the elastic restoring forces arising from nanoscale structural deformation. As such, they can be engaged to dynamically reconfigure the structure, providing a mechanism for strong opto-mechanical nonlinearity dependent upon the direction of light propagation, leading to transmission asymmetry at μW/μm2 intensities.

The interaction of circularly polarized light with matter is the basis for molecular circular dichroism spectroscopy, optical spin manipulation, and optical torques. However, chiroptical effects are usually hampered by weak chiral light-matter interaction. Nanophotonic structures can enhance optical intensity to boost interactions, but magnifying chiral effects requires that the near field remains chiral in the process. Here, we propose the conditions, limits and guidelines for enhancing different chiroptical effects near achiral metasurfaces with maximum chirality of the evanescent fields. We illustrate these conditions with arrays of metal and dielectric nanodisks and decompose their distinct electromagnetic metrics into propagating and evanescent Fourier orders. We prove that chirality metrics like circular dichroism and the degree of circular polarization, which go hand-in-hand in the far field for propagating plane waves, are incompatible in the evanescent near field. As a result, a nanostructure cannot be universally optimal for different chirality metrics and therefore applications. For example, arrays tailored for enhanced spin excitation with spatially uniform circular polarization destroy circular dichroism. Conversely, we predict a limit of maximum attainable circular dichroism in highly evanescent Fourier orders through a simple relation with the evanescent wavevector and polarization. We demonstrate that silicon nanodisk arrays can enhance chiral effects within these constraints. Our results define the limits on the ability of nanophotonic platforms to enhance different chiral light-matter interactions simultaneously. Our work provides design rules for diverse chiroptical applications such as molecular spectroscopy, information technology and optical nanomanipulation.

There is growing interest and technological opportunity in nanomechanics and the fundamentals of nano- to pico-scale dynamics, which derive from the fact that electromagnetic and quantum forces become stronger as the dimensions of objects decrease, competing with elastic forces at sub-micron scales; while movements become faster as mass decreases, achieving Gigahertz bandwidth at the nanoscale.We report on a novel approach to the visualization of such movements that is based on the detection of secondary electrons and photons emerging from the interaction of a focused electron beam with moving components of nano-objects. The technique extends the static (zero-frequency) imaging capabilities of a conventional scanning electron microscope to enable hyperspectral spatial mapping of fast (MHz-GHz) thermal and externally-driven nano- to pico-scale motion in nanostructures.