Reconfigurable Near‐field Enhancement with Hybrid Metal‐Dielectric Oligomers

Abstract

Tailoring of the near‐field properties of the nanostructures is a significant task for the control of radiation of nanoscale light sources as well as for sensing applications. Generally, this task is solved in plasmonic oligomers on the fabrication step by the choice of geometry or by controlling the excitation light during the experiments. Here, the pronounced modification of the near‐field pattern in hybrid gold‐silicon oligomers by femtosecond laser reshaping by visualizing it with aperture‐type near‐field optical microscope is demonstrated. This effect correlates with a moderate red‐shift of the broadband magnetic dipole resonance of the structure that occurs upon reshaping the gold component of the oligomers. The proposed all‐optical near‐field reconfiguration approach makes hybrid oligomers a promising platform for on‐demand engineering of local field enhancement in metadevices for data recording and sensing.

Femtosecond Laser-Assisted Formation of Hybrid Nanoparticles from Bi-Layer Gold–Silicon Films for Microscale White-Light Source

“…Zuev et al [ 12 ] demonstrated the fabrication of hybrid nanostructures with a magnetic optical response via femtosecond laser melting of asymmetrical metal–dielectric (Au/Si) nanoparticles created by lithographical methods. Furthermore, such asymmetrical hybrid nanostructures can be used to locally color the surface in a tunable way [ 13 ], as well as fano resonance [ 14 ] and near-field distribution [ 15 ].…”

Plasmonic nanosponges filled with silicon for enhanced white light emission

“…On the way of integration of plasmonics with the highrefractive dielectics, hybrid Si/Au(Ag) nanostructures with separated metallic and semiconductor parts were recently applied for surface coloring 10 , near-field and far-field tuning 11 , optical harmonics generation 12 , and fluorescence enhancement 13 . However, standard top-down approaches, combining these elements within a single nano-objects, are complicated and often restricted by the material properties.…”

Applications of Hybrid Metal‐Dielectric Nanostructures: State of the Art

“…This effect was observed with a near-field optical microscope. [247] Metallo-dielectric core-shell nanostructures play an important role in the development of more efficient sensing devices. In ref.…”

“…Apart from nonlinear frequency generation, nonlinear effects can also be used for the purpose of all‐optical dynamic tuning of the optical response of hybrid metal‐dielectric nanostructures. For example, metal‐dielectric metasurfaces allowing for dynamic beam steering, [ 314 ] tunable topological insulators, [ 315 ] and metamaterials reconfigurable by a fs laser pulse [ 247 ] were reported.…”

“…With this objective, aggregates of NPs (oligomers) have been considered. In, [ 247 ] the near‐field properties of oligomers of hybrid metal‐dielectric (gold‐silicon) NPs were modified by reshaping the nanostructure geometry by means of a femtosecond laser. Due to the reshaping of the gold components of the oligomers, there is a shift of the dipolar magnetic resonances, which enables to engineer the near‐field enhancement.…”