Periodic array-based substrates for surface-enhanced infrared spectroscopy

Abstract

At the beginning of the 1980s, the first reports of surface-enhanced infrared spectroscopy (SEIRS) surfaced. Probably due to signal-enhancement factors of only 10 1 to 10 3 , which are modest compared to those of surface-enhanced Raman spectroscopy (SERS), SEIRS did not reach the same significance up to date. However, taking the compared to Raman scattering much larger crosssections of infrared absorptions and the enhancement factors together, SEIRS reaches about the same sensitivity for molecular species on a surface in terms of the crosssections as SERS and, due to the complementary nature of both techniques, can valuably augment information gained by SERS. For the first 20 years since its discovery, SEIRS relied completely on metal island films, fabricated by either vapor or electrochemical deposition. The resulting films showed a strong variance concerning their structure, which was essentially random. Therefore, the increase in the corresponding signal-enhancement factors of these structures stagnated in the last years. In the very same years, however, the development of periodic array-based substrates helped SEIRS to gather momentum. This development was supported by technological progress concerning electromagnetic field solvers, which help to understand plasmonic properties and allow targeted design. In addition, the strong progress concerning modern fabrication methods allowed to implement these designs into practice. The aim of this contribution is to critically review the development of these engineered surfaces for SEIRS, to compare the different approaches with regard to their performance where possible, and report further gain of knowledge around and in relation to these structures.

Non-Absorbing Dielectric Materials for Surface-Enhanced Spectroscopies and Chiral Sensing in the UV

“…Nanophotonic devices have been intensively investigated aiming the development of new spectroscopic techniques such as surface-enhanced Raman spectroscopy (SERS) [ 1 , 2 , 3 , 4 ], surface-enhanced infrared absorption (SEIRA) [ 4 , 5 , 6 , 7 ], surface-enhanced fluorescence (SEF) [ 2 , 8 , 9 , 10 , 11 ] or chiral sensing [ 12 , 13 , 14 ], among others. Generally, these spectroscopic techniques rely on the hot-spots produced when nanostructures are illuminated under resonance.…”

Enhanced Graphene Plasmonic Mode Energy for Highly Sensitive Molecular Fingerprint Retrieval

“…[ 2,6 ] This technology employs the strong near fields of metallic plasmonic resonances that couple with the molecular vibrations to enlarge the spectroscopic signals. To date, various well‐designed metallic IR plasmonic nanostructures have been developed for SEIRAS with significant enhancements, [ 2,7,8 ] such as coupled arrays of nanoantennas, [ 9,10 ] fractal‐shaped antennas, [ 11 ] and perfect absorber structures, [ 12 ] etc. However, these IR nanostructures generally require lengths at levels of wavelength‐scale to match with the IR wavelengths, which limits the nanostructure array densities and the achievable field enhancements.…”

Refractive Index Sensing of Monolayer Molecules Using Both Local and Propagating Surface Plasmons in Mid-Infrared Metagrating

“…Although SPs-based sensors thus far have been mostly developed in visible and near-infrared regions, the mid-infrared spectral band has recently attracted considerable interest due to two main reasons [21][22][23][24]. One is the presence of the "fingerprint region", which refers to a spectral band having absorption lines of molecular vibration and rotation modes.…”