Vibrational overtones spectroscopy enabled by plasmonic nanoantennas

Daler R. Dadadzhanov, Tigran A. Vartanyan, Alina Karabchevsky

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

5 Scopus citations

Abstract

Infrared spectroscopy is very powerful tool to analyze the chemicals based on their molecular signatures. The registration of the fundamental vibrational modes that lie in the far IR is extensively explored, however the excitation of derivatives namely high harmonics molecular vibrations overtones is still a mystery. Although the absorption crosssection of molecular transition overtones is order of magnitude smaller compared to their fundamental vibrations, the research of overtones is of high importance if just would be possible to detect them. In this work, we show that the challenge in detection of molecular overtones may be overcome with localized surface plasmon resonance effect in gold nanorods antennas. We use N-Methylaniline as a probe molecule since we confirmed the excitation its molecular transitions overtones in near-infrared around 1.5 μm. We calculate absorption cross-section of gold nanorods with fixed diameter of 10 nm and different lengths varying from 80 to 160 nm surrounded by a homogeneous medium with the optical properties of N-Methylaniline, using the finite element method (FEM). To single out the contribution of the overtone modes, computations were repeated with N-Methylaniline replaced by the dispersionless media mimicking only the mean value of N-Methylaniline refractive index, n = 1.5712, and eliminating absorption. We show, that the differential absorption in the spectral range of the first overtone of the -NH vibration located at 1492 nm and the first overtone of the -CH vibration located at 1676 nm have both positive and negative values due to the shifting of the gold nanorod plasmon resonance band.

Original languageEnglish
Title of host publicationPlasmonics
Subtitle of host publicationDesign, Materials Fabrication, Characterization, and Applications XVI
EditorsDin Ping Tsai, Din Ping Tsai, Takuo Tanaka
PublisherSPIE
ISBN (Electronic)9781510620155
DOIs
StatePublished - 1 Jan 2018
EventPlasmonics: Design, Materials Fabrication, Characterization, and Applications XVI 2018 - San Diego, United States
Duration: 19 Aug 201823 Aug 2018

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume10722
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Conference

ConferencePlasmonics: Design, Materials Fabrication, Characterization, and Applications XVI 2018
Country/TerritoryUnited States
CitySan Diego
Period19/08/1823/08/18

Keywords

  • Gold nanorods
  • Localized surface plasmon resonance
  • Plasmonic nanoantenna
  • Vibrational overtones spectroscopy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

Fingerprint

Dive into the research topics of 'Vibrational overtones spectroscopy enabled by plasmonic nanoantennas'. Together they form a unique fingerprint.

Cite this