All‐Optical Reconfiguration of Ultrafast Dichroism in Gold Metasurfaces. Issue 10 (23rd March 2022)

• Record Type: Journal Article
• Authors: Schirato, Andrea; Toma, Andrea; Proietti Zaccaria, Remo; Alabastri, Alessandro; Cerullo, Giulio; Della Valle, Giuseppe; Maiuri, Margherita
• Is Part Of: Advanced optical materials. Volume 10:Issue 10(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-23
• Subjects: all‐optical switching -- photoinduced anisotropy -- pump–probe spectroscopy -- reconfigurable metasurfaces -- ultrafast nanophotonics; Optical materials -- Periodicals; Photonics -- Periodicals; 620.11295
• DOI: 10.1002/adom.202102549
• Languages: English
• ISSNs: 2195-1071

Abstract

Abstract: Optical metasurfaces have come into the spotlight as a promising platform for light manipulation at the nanoscale, including ultrafast all‐optical control via excitation with femtosecond laser pulses. Recently, dichroic metasurfaces have been exploited to modulate the polarization state of light with unprecedented speed. This work theoretically predicts and experimentally demonstrates by pump–probe spectroscopy the capability to reconfigure the ultrafast dichroic signal of a gold metasurface by simply acting on the polarization of the pump pulse, which is shown to reshape the spatio‐temporal distribution of the optical perturbation. The photoinduced anisotropic response, driven by out‐of‐equilibrium carriers and extinguished in a sub‐picosecond temporal window, is readily controlled in intensity by tuning the polarization direction of the excitation up to a full sign reversal. Hence, nonlinear metasurfaces are here demonstrated to offer the flexibility to tailor their ultrafast optical response in a fully all‐optically reconfigurable platform. Abstract : A combination of semiclassical modeling and pump–probe spectroscopy is exploited to demonstrate the all‐optical reconfiguration of the ultrafast nonlinear response in a plasmonic metasurface made of gold nanocrosses. It is shown that the pump polarization tuning can reshape the spatio‐temporal distribution of the photoinduced hot carriers to modulate the sub‐picosecond anisotropy up to a full sign reversal.