Metasurface Reconfiguration through Lithium‐Ion Intercalation in a Transition Metal Oxide

In the latest years the optical engineer's toolbox has welcomed a new\nconcept, the metasurface. In a metasurface, properly tailored material\ninclusions are able to reshape the electromagnetic field of an incident beam.\nChange of amplitude, phase and polarization can be addressed within a thickness\nof only a fraction of a wavelength. By means of this concept, a radical gain in\ncompactness of optical components is foreseen, even of the most complex ones;\nother unique features like that of analog computing have also been identified.\nWith this huge potential ready to be disclosed, lack of tunability is still a\nmain barrier to be broken. Metasurfaces must now be made reconfigurable, i.e.\nable to modify and memorize their state, possibly with a small amount of\nenergy. In this Communication we report low-energy, self-holding metasurface\nreconfiguration through lithium intercalation in a vanadium pentoxide layer\nintegrated within the photonic device. By a proper meta-atom design, operation\non amplitude and phase of linearly polarized light has been demonstrated. In\naddition, manipulation of circularly polarized light in the form of tunable\nchirality and tunable handedness-preserving reflection has been implemented.\nThese operations are accomplished using as low as 50 pJ/{\\mu}m^{2}, raising\nlithium intercalation in transition metal oxides as one of the most energy\nefficient self-holding tuning mechanisms known so far for metasurfaces, with\nsignificant perspectives in the whole field of nanophotonics.\n