Fabrication of porous microrings via laser printing and ion-beam post-etching

TL;DR

This paper presents a novel laser printing and ion-beam etching method to fabricate porous noble-metal microrings with tunable structures, enabling enhanced electromagnetic fields for spectroscopic bioidentification applications.

Contribution

The study introduces a new fabrication process combining pulsed-laser printing and ion-beam etching to create tunable porous microrings with enhanced plasmonic properties.

Findings

Porous microrings with tunable pore size were successfully fabricated.

Enhanced near-field electromagnetic fields were achieved, improving spectroscopic signals.

The method enables design of multifunctional plasmonic structures for bio-detection.

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.