ABSTRACT
The nanoscale identification of molecules is a driving force for the
knowledge in nanoscience and a key parameter in the further devel-
opment of nanotechnology such as nanoelectronics, biotechnology,
or green technology. Vibration of atoms in molecules provides
valuable information on chemical species and is considered as a
molecular “finger-print.” For example, vibration-based microscopy
has recently shown the ability to track molecules in living tissues
without the need for fluorescent labels [1, 2]. Furthermore,
molecular vibrations or phonons in crystals are also sensitive to
intrinsic perturbations (defects, plasmon-phonon coupling, etc.)
and extrinsic perturbation (charge transfer, pressure, temperature,
optical processes, etc.). Vibrations can be probed by only a limited
number of techniques: infrared spectroscopy, inelastic neutron
scattering, Raman scattering, and, more recently, inelastic scanning
tunneling spectroscopy [3]. The last one “visualizes” the chemical
nature of atoms and molecules on a surface but requires ultra-
high vacuum (UHV) and very low temperature. The inelastic Raman
scattering provides very rich information and does not require
special sample preparation, but faces a low scattering cross section
(10−31-10−26 cm2/molecule [4, 5]), and Abbe’s diffraction limited spatial resolution.
