The nanomechanical metamaterials offer the possibilities of manipulating exotic electromagnetic properties on demand. Such metamaterial exhibit profound electro-optical, magneto-optical and acousto-optical switching and modulation, optical nonlinearity for modulating light with light, asymmetric transmission, and tunable chirality. The electromagnetic properties of nanomechanical metamaterial structure strongly depend on the spatial arrangement of its building blocks. By constructing metamaterials on elastically deformable scaffolds we can dynamically control the nanoscale spacing among constituent elements across the entire metamaterial array with external stimuli. Based on this approach, we use electrostatic, Lorentz, near field optical forces and sound to drive high-contrast, high-speed active tuning, modulation and switching of photonic metamaterial properties and to deliver exotic electromagnetic properties. We also report a novel approach to the visualization of nanoscale movements of picometre scale Brownian and stimulation movements of the individual building blocks of these functional metamaterials.
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.