Single-nanoantenna driven nanoscale control of the VO₂ insulator to metal transition

Abstract

The ultrafast concentration of electromagnetic energy in nanoscale volumes is one of the key features of optical nanoantennas illuminated at their surface plasmon resonances. Here, we drive the insulator to metal phase transition in vanadium dioxide (VO2) using a laser-induced pumping effect obtained by positioning a single gold nanoantenna in proximity to a VO2 thermochromic material. We explore how the geometry of the single nanoantenna affects the size and permittivity of the nanometer-scale VO2 regions featuring phase transition under different pumping conditions. The results reveal that a higher VO2 phase transition effect is obtained for pumping of the longitudinal or transversal localized surface plasmon depending on the antenna length. This characterization is of paramount importance since the single nanoantennas are the building blocks of many plasmonic nanosystems. Finally, we demonstrate the picosecond dynamics of the VO2 phase transition characterizing this system, useful for the realization of fast nano-switches. Our work shows that it is possible to miniaturize the hybrid plasmonic-VO2 system down to the single-antenna level, still maintaining a controllable behavior, fast picosecond dynamics, and the features characterizing its optical and thermal response.

All-optical switching based on plasmon-induced Enhancement of Index of Refraction

“…To improve the performance of nonlinear optical switches, they are usually equipped with plasmonic or resonant nanostructures to exploit their field enhancement and confinement features 6 – 9 . Other switching schemes involve the hybridization of metamaterials by functional components such as semiconductors, carbon nanotubes, graphene, liquid crystals, and phase-change materials 10 – 15 . However, the aforementioned switching mechanisms generally suffer from unsatisfactory response time and/or high power requirements.…”

“…This effect is not only limited by the narrow band but also by its weak response. Typically, in an optical switch based on PIT, the transparency window of the medium is reversibly shifted in a wavelength range to provide the ON and OFF states of the switch by applying a light-induced change in the refractive index of a nonlinear material integrated with plasmonic constituents 15 , 16 . Furthermore, a large resonant index of refraction with vanishing absorption has also been reported in quantum optics.…”

Review of the VO2 smart material applications with emphasis on its use for spacecraft thermal control

“…The ultrafast concentration of electromagnetic energy in nanoscale volumes is one of the key features of optical nanoantennas illuminated at their surface plasmon Resonances. Bergamini et al (2021) obtained a higher VO 2 phase transition effect for pumping of the longitudinal or transversal localized surface plasmon depending on the antenna length. This characterization very important since the single nano-antennas are the building blocks of many plasmonic nano systems.…”

Plasmonic Hot-Electron Injection Driving Ultrafast Phase Transition in Self-Supported VO2 Films for All-Optical Modulation

“…Surface plasmon polaritons at the interface of VO 2 and gold layers can also induce the insulator-to-metal transition in VO 2 . Recently, Bergamini et al drove the IMT in VO 2 using a single gold nanoantenna and explored how the geometry of the nanorod nanoantenna affected the size and permittivity of the nanometer-scale VO 2 regions featuring a phase transition . However, the ultrafast differential transmission signals are usually low in these works, which is unsuitable for realizing all-optical modulators with large modulation depths.…”

“…33 Recently, Bergamini et al drove the IMT in VO 2 using a single gold nanoantenna and explored how the geometry of the nanorod nanoantenna affected the size and permittivity of the nanometer-scale VO 2 regions featuring a phase transition. 34 However, the ultrafast differential transmission signals are usually low in these works, which is unsuitable for realizing alloptical modulators with large modulation depths. In this paper, we presented ultrafast all-optical switching in a composite structure of a self-supported VO 2 film on a gold nanoshell grating.…”