Antenna-assisted picosecond control of nanoscale phase transition in vanadium dioxide

Abstract

Nanoscale devices in which the interaction with light can be configured using external control signals hold great interest for next-generation optoelectronic circuits. Materials exhibiting a structural or electronic phase transition offer a large modulation contrast with multi-level optical switching and memory functionalities. In addition, plasmonic nanoantennas can provide an efficient enhancement mechanism for both the optically induced excitation and the readout of materials strategically positioned in their local environment. Here, we demonstrate picosecond all-optical switching of the local phase transition in plasmonic antenna-vanadium dioxide (VO2) hybrids, exploiting strong resonant field enhancement and selective optical pumping in plasmonic hotspots. Polarization- and wavelength-dependent pump–probe spectroscopy of multifrequency crossed antenna arrays shows that nanoscale optical switching in plasmonic hotspots does not affect neighboring antennas placed within 100 nm of the excited antennas. The antenna-assisted pumping mechanism is confirmed by numerical model calculations of the resonant, antenna-mediated local heating on a picosecond time scale. The hybrid, nanoscale excitation mechanism results in 20 times reduced switching energies and 5 times faster recovery times than a VO2 film without antennas, enabling fully reversible switching at over two million cycles per second and at local switching energies in the picojoule range. The hybrid solution of antennas and VO2 provides a conceptual framework to merge the field localization and phase-transition response, enabling precise, nanoscale optical memory functionalities.

Light‐Induced Tuning and Reconfiguration of Nanophotonic Structures

“…A hybrid VO 2 metasurface switched by a sub‐100‐fs pulse was reported in Ref. []. A metasurface operating at the near‐IR range consists of an array of crossed gold nanoantennas fabricated on top of a VO 2 film.…”

Ultrafast Insulator-Metal Transition in VO2 Nanostructures Assisted by Picosecond Strain Pulses

“…In this case, the compressive and tensile components of the picosecond strain pulse should notably increase or decrease the threshold value for PIPT. In such a system of well-defined nanoelements the picosecond-strain-assisted enhancement or suppression of the ultrafast PIPT may lead to prospective applications in CMOS and photonic technologies [57][58][59][60]. Since dynamical strain may be localized down to nanometer scale [61], it can be used as a tool for selective control of single VO2 nanoelements.…”

Vanadium Dioxide: The Multistimuli Responsive Material and Its Applications

“…Integrating nanoantenna structures with materials is an efficient way to promote their optical properties. The antenna‐assisted, THz‐induced VO 2 film was demonstrated with the 5‐times faster recovery duration as well as the 20‐times lower switching energy than the plain VO 2 film . Moreover, the nonlinear THz transmission response of VO 2 can also be significantly enhanced by the antenna resonance effect .…”