Title: Fabrication of porous microrings via laser printing and ion-beam post-etching,
Abstract: Pulsed-laser dry printing of noble-metal microrings with a tunable internal
porous structure, which can be revealed via an ion-beam etching post-procedure,
was demonstrated. Abundance and average size of the pores inside the microrings
were shown to be tuned in a wide range by varying incident pulse energy and a
nitrogen doping level controlled in the process of magnetron deposition of the
gold film in the appropriate gaseous environment. The fabricated porous
microrings were shown to provide many-fold near-field enhancement of incident
electromagnetic fields, which was confirmed by mapping of the characteristic
Raman band of a nanometer-thick covering layer of Rhodamine 6G dye molecules
and supporting finite-difference time-domain calculations. The proposed laser
printing/ion-beam etching approach is demonstrated to be a unique tool aimed at
designing and fabricating multifunctional plasmonic structures and metasurfaces
for spectroscopic bioidentification based on surface-enhanced infrared
absorption, Raman scattering and photoluminescence detection schemes.