Selectively accessing the hotspots of optical nanoantennas by self-aligned dry laser ablation. Issue 37 (14th September 2020)

• Record Type: Journal Article
• Authors: Schäfer, Christian; Perera, Pradeep N.; Laible, Florian; Olynick, Deirdre L.; Schwartzberg, Adam M.; Weber-Bargioni, Alexander; Cabrini, Stefano; Schuck, P. James; Kern, Dieter P.; Fleischer, Monika
• Is Part Of: Nanoscale. Volume 12:Issue 37(2020)
• Page Start: 19170
• Page End: 19177
• Publication Date: 2020-09-14
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/d0nr04024j
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : Self-aligned laser ablation is demonstrated to selectively access the nano-volumes of high near-field enhancement at nanoantenna tips for functionalization. Abstract : Plasmonic nanostructures serve as optical antennas for concentrating the energy of incoming light in localized hotspots close to their surface. By positioning nanoemitters in the antenna hotspots, energy transfer is enabled, leading to novel hybrid antenna-emitter-systems, where the antenna can be used to manipulate the optical properties of the nano-objects. The challenge remains how to precisely position emitters within the hotspots. We report a self-aligned process based on dry laser ablation of a calixarene that enables the attachment of molecules within the electromagnetic hotspots at the tips of gold nanocones. Within the laser focus, the ablation threshold is exceeded in nanoscale volumes, leading to selective access of the hotspot areas. A first indication of the site-selective functionalization process is given by attaching fluorescently labelled proteins to the nanocones. In a second example, Raman-active molecules are selectively attached only to nanocones that were previously exposed in the laser focus, which is verified by surface enhanced Raman spectroscopy. Enabling selective functionalization is an important prerequisite e.g. for preparing single photon sources for quantum optical technologies, or multiplexed Raman sensing platforms.