Experimental verification of field-enhanced molecular vibrational scattering at single infrared antennas

Fuente: arXiv
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Autori principali: Virmani, Divya, Maciel-Escudero, Carlos, Hillenbrand, Rainer, Schnell, Martin
Natura: Preprint
Pubblicazione: 2024
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author Virmani, Divya
Maciel-Escudero, Carlos
Hillenbrand, Rainer
Schnell, Martin
author_facet Virmani, Divya
Maciel-Escudero, Carlos
Hillenbrand, Rainer
Schnell, Martin
contents Surface-enhanced infrared absorption (SEIRA) spectroscopy exploits the field enhancement near nanophotonic structures for highly sensitive characterization of (bio)molecules. The vibrational signature observed in SEIRA spectra is typically interpreted as field-enhanced molecular absorption. Here we study molecular vibrations in the near field of single antennas and show that the vibrational signature can be equally well explained by field-enhanced molecular scattering. Although the infrared scattering cross section of molecules is negligible compared to their absorption cross section, the interference between the molecular-scattered field and the incident field enhances the spectral signature caused by molecular vibrational scattering by 10 orders of magnitude, thus becoming as large as that of field-enhanced molecular absorption. We provide experimental evidence that field-enhanced molecular scattering can be measured, scales in intensity with the fourth power of the local field enhancement and fully explains the vibrational signature in SEIRA spectra in both magnitude and line shape. Our work may open new paths for developing highly sensitive SEIRA sensors that exploit the presented scattering concept.
format Preprint
id arxiv_https___arxiv_org_abs_2401_09104
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Experimental verification of field-enhanced molecular vibrational scattering at single infrared antennas
Virmani, Divya
Maciel-Escudero, Carlos
Hillenbrand, Rainer
Schnell, Martin
Optics
Surface-enhanced infrared absorption (SEIRA) spectroscopy exploits the field enhancement near nanophotonic structures for highly sensitive characterization of (bio)molecules. The vibrational signature observed in SEIRA spectra is typically interpreted as field-enhanced molecular absorption. Here we study molecular vibrations in the near field of single antennas and show that the vibrational signature can be equally well explained by field-enhanced molecular scattering. Although the infrared scattering cross section of molecules is negligible compared to their absorption cross section, the interference between the molecular-scattered field and the incident field enhances the spectral signature caused by molecular vibrational scattering by 10 orders of magnitude, thus becoming as large as that of field-enhanced molecular absorption. We provide experimental evidence that field-enhanced molecular scattering can be measured, scales in intensity with the fourth power of the local field enhancement and fully explains the vibrational signature in SEIRA spectra in both magnitude and line shape. Our work may open new paths for developing highly sensitive SEIRA sensors that exploit the presented scattering concept.
title Experimental verification of field-enhanced molecular vibrational scattering at single infrared antennas
topic Optics
url https://arxiv.org/abs/2401.09104