Spectral Engineering via Complex Patterns of Circular Nano-object Miniarrays: I. Convex Patterns Tunable by Integrated Lithography Realized by Circularly Polarized Light

Abstract

Illumination of colloid sphere monolayers by circularly polarized beams enables the fabrication of concave patterns composed of circular nanohole miniarrays that can be transferred into convex metal nano-object patterns via a lift-off procedure. Unique spectral and near-field properties are achievable by controlling the geometry of the central nanoring and quadrumer of slightly rotated satellite nanocrescents and by selecting those azimuthal orientations that promote localized plasmon resonances. The spectral and near-field effects of hexagonal patterns composed of uniform gold nanorings and nanocrescents, which can be prepared by transferring masks fabricated by a perpendicularly and obliquely incident single homogeneous circularly polarized beam, were studied to uncover the supported localized plasmonic modes. Artificial rectangular patterns composed of a singlet nanoring and singlet nanocrescent as well as quadrumer of four nanocrescents were investigated to analyze the effect of nano-object interactions and lattice type. It was proven that all nanophotonical phenomena are governed by the azimuthal orientation independent localized resonance on the nanorings and by the C2, C1, and U resonances on the nanocrescents in case of $\bar {E}$ Ē -field direction perpendicular and parallel to their symmetry axes. The interaction between localized surface plasmon resonances on individual nano-objects is weak, whereas scattered photonic modes have a perturbative role at the Rayleigh anomaly only on the larger periodic rectangular pattern of miniarrays. Considerable fluorescence enhancement of dipolar emitters is achievable at spectral locations promoting the C and U resonances on the constituent nano-object.

Optimalizált nanoplazmonika

“…A kolloidgömb monorétegek interferáló nyalábokkal történő kivilágításával megvalósítható integrált litográfiával létrehozható komplementer konkáv és konvex nano-objektumokból felépülő struktúrák spektrális és közeltérbeli hatásait vizsgáltuk. Olyan komplex struktúrákat tanulmányoztunk, amelyek a 100 nm átmérőjű arany kolloidgömbök 60° azimutális orientációban elhelyezett monorétegének 400 nm-es cirkulárisan polarizált fénnyel történő kivilágításával hozhatók létre, két 12.83° szögben beeső interferáló nyalábbal (5. ábra) [5,6].…”

Spectral engineering via complex patterns of circular nano-object miniarrays: I. convex patterns tunable by integrated lithography realized by circularly polarized light

“…3b, c and Fig. 4-8/b) [49][50][51]. Localised plasmon resonances on the nanorings and nanocrecents are distinguished by using r and c in the abbreviations.…”

“…In this paper we present complex structures, which are composed of convex miniarrays of a central nanoring and satellite nanocrescents, arrayed in a rectangular pattern. These structures can be fabricated by combining colloid sphere and interference lithography, in a two-steps procedure [46][47][48][49]. The interferometric illumination of colloid-sphere monolayers (IICSM) enables the direct structuring of positive resists, whereas the masks can be transferred into convex patterns by a lift-off procedure.…”

“…To analyze the role of nano-object inter-actions and the lattice type in the collective resonance, artificial rectangular patterns of a singlet nanoring and singlet nanocrescent as well as quadrumer of four nanocrescents were investigated. A comparative study about the spectral and near-field effects of concave and convex patterns, that are achievable via IICSM directly and via a consecutive lift-off procedure, is provided as well in our previous work and in an upcoming paper [49,51].…”

Spectral engineering via complex patterns of circular nano-object miniarrays: II. concave patterns tunable by integrated lithography realized by circularly polarized light

“…Multiscale periodic colloidal assemblies were created by a method that combines thermo-responsive depletion with pre-patterned surface features [44]. In our previous studies we have presented the interferometric illumination of colloid sphere monolayers (IICSM) that enables to tune large number of geometrical parameters independently [45][46][47][48]. The method combines colloid sphere (CS) and interference lithography (IL) and synthesizes all advantages of these methods, thus providing a good tool to fabricate versatile patterns.…”