Cavity-enhanced Raman Microscopy of Individual Carbon Nanotubes
Abstract
Raman spectroscopy reveals chemically specific information and provides label-free insight into the molecular world. However, the signals are intrinsically weak and call for enhancement techniques. Here, we demonstrate Purcell enhancement of Raman scattering in a tunable high-finesse microcavity, and utilize it for molecular diagnostics by combined Raman and absorption imaging. Studying individual single-wall carbon nanotubes, we identify crucial structural parameters such as nanotube radius, electronic structure and extinction cross-section. We observe a 320-times enhanced Raman scattering spectral density and an effective Purcell factor of 6.2, together with a collection efficiency of 60%. Potential for significantly higher enhancement, quantitative signals, inherent spectral filtering and absence of intrinsic background in cavity-vacuum stimulated Raman scattering render the technique a promising tool for molecular imaging. Furthermore, cavity-enhanced Raman transitions involving localized excitons could potentially be used for gaining quantum control over nanomechanical motion and open a route for molecular cavity optomechanics.
Keywords
Cite
@article{arxiv.1508.06810,
title = {Cavity-enhanced Raman Microscopy of Individual Carbon Nanotubes},
author = {Thomas Hümmer and Jonathan Noe and Matthias S. Hofmann and Theodor W. Hänsch and Alexander Högele and David Hunger},
journal= {arXiv preprint arXiv:1508.06810},
year = {2016}
}