Light-driven nanoscale vectorial currents

Abstract

Controlled charge flows are fundamental to many areas of science and technology, serving as carriers of energy and information, as probes of material properties and dynamics1 and as a means of revealing2,3 or even inducing4,5 broken symmetries. Emerging methods for light-based current control5–16 offer particularly promising routes beyond the speed and adaptability limitations of conventional voltage-driven systems. However, optical generation and manipulation of currents at nanometre spatial scales remains a basic challenge and a crucial step towards scalable optoelectronic systems for microelectronics and information science. Here we introduce vectorial optoelectronic metasurfaces in which ultrafast light pulses induce local directional charge flows around symmetry-broken plasmonic nanostructures, with tunable responses and arbitrary patterning down to subdiffractive nanometre scales. Local symmetries and vectorial currents are revealed by polarization-dependent and wavelength-sensitive electrical readout and terahertz (THz) emission, whereas spatially tailored global currents are demonstrated in the direct generation of elusive broadband THz vector beams17. We show that, in graphene, a detailed interplay between electrodynamic, thermodynamic and hydrodynamic degrees of freedom gives rise to rapidly evolving nanoscale driving forces and charge flows under the extremely spatially and temporally localized excitation. These results set the stage for versatile patterning and optical control over nanoscale currents in materials diagnostics, THz spectroscopies, nanomagnetism and ultrafast information processing.

Metamaterial Induced Symmetry Engineering of Berry Curvature for Spin Light Detection

“…Therefore, high polarization ratios and responsivities were achieved in mid-infrared photodetection of linearly polarized light and circularly polarized light, even utilizing the topologically trivial photothermoelectric effect. Pettine et al lately revealed the interplay mechanism among electrodynamics, thermodynamics and hydrodynamics which commonly contribute to the plasmonic metamaterials tailored nanoscale vectoral current, and pointed out the wide platform and rich phenomena these nanoscale meta-atoms would create in light-matter interaction …”