Active Plasmonics: Principles, Structures, and Applications

Abstract

Active plasmonics is a burgeoning and challenging subfield of plasmonics. It exploits the active control of surface plasmon resonance. In this review, a first-ever in-depth description of the theoretical relationship between surface plasmon resonance and its affecting factors, which forms the basis for active plasmon control, will be presented. Three categories of active plasmonic structures, consisting of plasmonic structures in tunable dielectric surroundings, plasmonic structures with tunable gap distances, and self-tunable plasmonic structures, will be proposed in terms of the modulation mechanism. The recent advances and current challenges for these three categories of active plasmonic structures will be discussed in detail. The flourishing development of active plasmonic structures opens access to new application fields. A significant part of this review will be devoted to the applications of active plasmonic structures in plasmonic sensing, tunable surface-enhanced Raman scattering, active plasmonic components, and electrochromic smart windows. This review will be concluded with a section on the future challenges and prospects for active plasmonics.

From active plasmonic devices to plasmonic molecular electronics

“…By controlling the characteristics of the molecule, it is possible to modify (i) the apparent dielectric function of the environment of the NP; (ii) the electromagnetic coupling between the plasmon and the molecule; or (iii) that between two adjacent NPs which tune the LSPR frequency. In this work we focus on electrochemical input but electrical, optical, mechanical, thermal and chemical inputs can also be used and have been reviewed elsewhere …”

“…In this work we focus on electrochemical input but electrical, optical, mechanical, thermal and chemical inputs can also be used and have been reviewed elsewhere. [15][16][17] The first active molecular plasmonic devices were developed using electrochemistry on plasmonic electrodes and were derived from molecular actuators. 18 Deposition of an electroactive thin film on the NPs makes it possible to modulate the LSPR by means of the potential applied to the electrode, using the oxido-reduction properties of the deposited layer.…”

The 3D Design of Multifunctional Silver Nanoparticle Assemblies Embedded in Dielectrics

“…Many articles in the literature are devoted to optical properties and the dependence of the SPR of plasmonic materials on their composition, geometry, and spatial arrangement has been extensively studied . The recent keen interest for active plasmonic nanostructures (for which the LSPR can be actively controlled) has boosted the search of the ideal embedding matrix for an additional control of SPR in plasmonics structures . The most efficient metals for electromagnetic field exaltation are silver, gold, or copper, among which silver presents the highest LSPR in the visible range with a very elevated quality factor .…”

“…[9,10] The recent keen interest for active plasmonic nanostructures (for which the LSPR can be actively controlled) has boosted the search of the ideal embedding matrix for an additional control of SPR in plasmonics structures. [11] The most efficient metals for electromagnetic field exaltation are silver, gold, or copper, among which silver presents the highest LSPR in the visible range with a very elevated quality factor. [12] Even if AgNPs are the best plasmonic antenna, their reactivity in air has strongly delayed their widespread use for plasmonic devices.…”

Actively Tunable Collective Localized Surface Plasmons by Responsive Hydrogel Membrane

“…[14] Several strategies have been explored for the reversible actuating of LSPs supported by metallic nanostructures. [15] Collective (lattice) localized surface plasmons (cLSP) with actively tunable and extremely narrow spectral characteristics are reported. They are supported by periodic arrays of gold nanoparticles attached to a stimuli-responsive hydrogel membrane, which can on demand swell and collapse to reversibly modulate arrays period and surrounding refractive index.…”