Realizing Anderson localization of surface plasmon polaritons and enhancing their interactions with excitons in 2D disordered nanostructures

Abstract

Surface plasmon polaritons (SPPs) propagating on a metal–dielectric interface suffer from inevitable energy losses originating from metals, especially in a visible regime, which degrades the quality of SPP-based devices. However, if the size of the devices is sufficiently miniaturized, we can thereby limit the propagation length of the signals and effectively circumvent the problems of large propagation losses. Anderson localization is a possible approach to squeeze SPPs. In this Letter, we experimentally demonstrate the Anderson localization of SPPs at optical frequencies in two-dimensional (2D) nanostructures. By increasing the positional disorder of the silver nanohole arrays on a glass substrate, strong 2D localization of SPPs appears with an exponentially decreased electric field, reduced propagation length, and the rapid disappearance of the autocorrelation coefficient. Moreover, we manage to realize the localized SPP-exciton interactions in the 2D disordered silver nanoarrays combined with fluorescent dye molecules. Due to the disorder in the nanoarray, the collected photoluminescence from fluorescent dye molecules is enhanced by over three orders of magnitude compared to that on the silver film without nanostructures. Our study extends Anderson localization of SPPs at the visible regime to 2D disordered systems and provides a unique way to enhance light–matter interaction in SPP-based nanodevices.

Theory of Multiple Scattering Enhanced Single Particle Plasmonic Sensing

“…As scatterer density increases further the mean enhancement reaches a maximum of ∼367 at an optimal density of n = 0.49/λ 0 2 ( l s = 3.51λ 0 ), before then decreasing at higher n , eventually dropping below one, indicating that at extremely high densities, multiple scattering acts to decrease the scattered signal perturbation on average. We attribute this decrease to SPP localization effects which restrict the impact of the additional particle to a region of the order of the localization length in size. In particular, we note the localization length of a 2D system can be estimated as ξ = l s exp­(πRe­[ k SPP ] l s /2), which becomes comparable to the system size for l s ≈ 0.73λ 0 in our simulations.…”

Maximal Anderson Localization and Suppression of Surface Plasmons in Two-Dimensional Random Au Networks

“…To measure the localization from the EEL spectrum images, we employed two different localization measures frequently used in the context of AL [14]: (I) the azimuthally averaged ( ...…”

“…Meanwhile, AL of classical optical and infrared fields has been observed in a variety of related systems, such as nanoparticle (NP) aggregates [12] and lithographically produced cavities [13,14]. Moreover, various applications such as Surface Enhanced Raman Spectroscopy (SERS) [5,15], the effective generation of non-linear optics on the nanoscale (e.g., four wave mixing, nonlinear absorption, harmonic generation) [16], random lasing [17,18], and bistable optical transistor [19], have been discussed and partially realized.…”

Polarized Photoluminescence Enhancement of Monolayer MoS2 Coupled with Plasmonic Salisbury‐Type Absorber

“…Fortunately, the plasmonic nanostructures can be integrated with TMDs to enhance the quantum efficiency [27] and suppress the quantum decoherence [28] by the enhancement of exciton-plasmon coupling owing to their extraordinary capability of localizing electromagnetic field within the subwavelength scale. [29][30][31][32] Recently, many hybrid TMDs-plasmonic systems, including metallic nanoparticle arrays, nanoslits, and nanoarrays, were widely explored to investigate the exciton-plasmon coupling characterized by the enhancement and the polarization control of PL emission. [33][34][35][36][37][38][39][40][41][42][43] In principle, the optically bright exciton of TMDs is composed of the conduction and valence electronic states with the same spin projections in each valley.…”