Tuning of Spectral and Angular Distribution of Scattering from Single Gold Nanoparticles by Subwavelength Interference Layers

in: Nano Letters (2014)
Wirth, Janina; Garwe, Frank; Bergmann, Joachim; Paa, Wolfgang; Csáki, Andrea; Stranik, Ondrej; Fritzsche, Wolfgang
Localized surface plasmon resonance (LSPR) as the resonant oscillation of conduction electrons in metal nanostructures upon light irradiation is widely used for sensing as well as nanoscale manipulation. The spectral resonance band position can be controlled mainly by nanoparticle composition, size, and geometry and is slightly influenced by the local refractive index of the near- field environment. Here we introduce another approach for tuning, based on interference modulation of the light scattered by the nanostructure. Thereby, the incoming electric field is wavelength-dependent modulated in strength and direction by interference due to a subwavelength spacer layer between nanoparticle and a gold film. Hence, the wavelength of the scattering maximum is tuned with respect to the original nanoparticle LSPR. The scattering wavelength can be adjusted by a metallic mirror layer located 100−200 nm away from the nanoparticle, in contrast to near-field gap mode techniques that work at distances up to 50 nm in the nanoparticle environment. Thereby we demonstrate, for the first time at the single nanoparticle level, that dependent on the interference spacer layer thickness, different distributions of the scattered signal can be observed, such as bell-shaped or doughnut-shaped point spread functions (PSF). The tuning effect by interference is furthermore applied to anisotropic particles (dimers), which exhibit more than one resonance peak, and to particles which are moved from air into the polymeric spacer layer to study the influence of the distance to the gold film in combination with a change of the surrounding refractive index.

Cookies & Skripte von Drittanbietern

Diese Website verwendet Cookies. Für eine optimale Performance, eine reibungslose Verwendung sozialer Medien und aus Werbezwecken empfiehlt es sich, der Verwendung von Cookies & Skripten durch Drittanbieter zuzustimmen. Dafür werden möglicherweise Informationen zu Ihrer Verwendung der Website von Drittanbietern für soziale Medien, Werbung und Analysen weitergegeben.
Weitere Informationen finden Sie unter Datenschutz und im Impressum.
Welchen Cookies & Skripten und der damit verbundenen Verarbeitung Ihrer persönlichen Daten stimmen Sie zu?

Sie können Ihre Einstellungen jederzeit unter Datenschutz ändern.