Normal and anomalous plasmonic lattice modes of gold nanodisk arrays in inhomogeneous media

Abstract

We study plasmonic lattice modes in two dimensional arrays of large metallic nanodisks in strongly inhomogeneous environments with controlled dielectric asymmetries. This is done within the two limits of positive (air/substrate) and negative (Si/substrate) asymmetries. In the former, the nanodisks are exposed to air, while in the latter, they are fully embedded in a dielectric material with a refractive index much higher than that of the glass substrate (Si). Our results show that in the air/substrate limit, the arrays can mainly support two distinct visible and infrared peaks associated with the optical coupling of multipolar plasmonic resonances of nanodisks in air and substrate (normal modes). As the nanodisks are gradually embedded in Si, i.e., going from the positive to negative asymmetry limit, the visible peak undergoes more than 200 nm red shift without significant mode degradation. Our results show that as this transition happens, a third peak (anomalous mode) becomes dominant. The amplitude and wavelength of this peak increase quadratically with the thickness of the Si layer, indicating formation of a unique collective mode. We study the impact of this mode on the emission semiconductor quantum dots, demonstrating they become much brighter as the result of the long-reach plasmonic fields of the nanodisks when the arrays are in this mode.

Second Harmonic Spectroscopy of Surface Lattice Resonances

“…To explore the limits of these applications, future work should focus on the importance of the environment surrounding the nanoparticle arrays. 73,74 ■ ASSOCIATED CONTENT * S Supporting Information…”

“…This process could therefore enable ultrafast probes of the refractive index and could be useful for monitoring chemical reactions, for example, catalysis by the nanoparticles. To explore the limits of these applications, future work should focus on the importance of the environment surrounding the nanoparticle arrays. , …”

Plasmonic Lattice Mode Formed by Ag Nanospheres on Silica Pillar Arrays

“…After that, the transmittance turns to rise again. This is the typical PLM of the periodic metallic nanoparticles [1,2].…”

“…periodic arrays of metallic nanoparticles [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. When the periodic arrays of the metallic nanoparticles are illuminated by the light with the wavelength around the period of the arrays, the transmittance varies rapidly from the maximum to the minimum in a narrow wavelength band [5].…”

Investigation of Lattice Plasmon Modes in 2D Arrays of Au Nanoantennas

“…Recently, an in-depth study of these modes has been theoretically performed by investigating in details arrays of Au monomers and dimers [21,[34][35][36]. A related experimental verification is not simple, since arrays with different periodicities have to be fabricated by means of very precise nanotechnology tools to ensure high-quality nanoscale morphological features over large areas.…”