Active molecular plasmonics: tuning surface plasmon resonances by exploiting molecular dimensions

Abstract

Molecular plasmonics explores and exploits the molecule-plasmon interactions on metal nanostructures to harness light at the nanoscale for nanophotonic spectroscopy and devices. With the functional molecules and polymers that change their structural, electrical, and/or optical properties in response to external stimuli such as electric fields and light, one can dynamically tune the plasmonic properties for enhanced or new applications, leading to a new research area known as active molecular plasmonics (AMP). Recent progress in molecular design, tailored synthesis, and self-assembly has enabled a variety of scenarios of plasmonic tuning for a broad range of AMP applications. Dimension (i.e., zero-, two-, and threedimensional) of the molecules on metal nanostructures has proved to be an effective indicator for defining the specific scenarios. In this review article, we focus on structuring the field of AMP based on the dimension of molecules and discussing the state of the art of AMP. Our perspective on the upcoming challenges and opportunities in the emerging field of AMP is also included.

Optimizing plasmonic nanoantennas via coordinated multiple coupling

“…Plasmonic nanoantennas continue to attract increased attention due to their capability of confining free-space electromagnetic waves into a sub-wavelength region with high field enhancement 1 2 3 4 5 6 7 8 9 10 11 12 13 , which enables a variety of cutting-edge applications such as surface-enhanced Raman spectroscopy (SERS) 14 15 16 17 18 19 , single-molecule detection 20 21 , high-sensitive photodetection 22 , near-field optical trapping 23 , magnetic recording 24 25 , and nanoscale light sources 26 . The field enhancement (FE) of the nanoantennas is one of the most important factors for all these applications.…”

Active metamaterial nearly perfect light absorbers: a review [Invited]

“…Responsive polymers are another type of materials with tunable characteristics that can consequently be employed as building block components in active MPAs. Responsive polymers that show an active response to heat, light, electricity, or chemicals can be cut to smaller chains [107]. This attribute enables the switching of polymer properties with external stimuli.…”

“…There are several different categories of active materials that are available in nature and that can be employed to design active metamaterials. These materials can be categorized as transparent conductive oxides (TCOs) [67,[86][87][88][89][90], superconductors [91,[92][93][94][95][96], ferroelectrics [such as strontium titanate (STO) and BaSrTiO 3 (BST)] [69,85], ferrites and magnetically tunable materials [97][98][99][100][101], liquid crystals (LCs) [102][103][104][105][106], molecules and polymers [107,108], liquid iron [109,110], semiconductors [71], graphene [111][112][113][114][115][116], and phase-change materials (PCMs) [117][118][119][120][121]. The previous reviews about metamaterial light absorbers have mainly focused on the investigation of theoretical backgrounds, different designs, and applications of passive structures [122][123][124][125]…”

Unidirectional reflectionless light propagation at exceptional points

“…SPPs, which are surface waves propagating along the interface between a metal and a dielectric [49], can concentrate electromagnetic energy at volumes of subwavelength scale and enable the manipulation of light beyond the diffraction limit [50][51][52][53][54][55][56][57][58][59]. Yang and Mei introduced a periodic PT-symmetric modulation on the effective refractive index of a metal-dielectric waveguide in the cylindrical coordinate system.…”