What is tip enhanced Raman scattering, or TERS?
Tip enhanced Raman scattering (TERS) combines surface enhanced Raman spectroscopy (SERS) with Raman-AFM analysis. The goal of this exciting research area is to offer true nanometer scale spatial resolution for Raman. The principles of TERS are simple, although the practical use of TERS is complex, and requires considerable expertise in terms of spectroscopy and optics. Surface enhanced Raman scattering (SERS) can provide orders of magnitude increases in Raman signal intensity. If the tip of an atomic force microscope (AFM) is made SERS active (by coating with a SERS active metal or metal nanoparticles) then the SERS effect would be expected to occur only within the immediate vicinity of the tip. Since the tip has dimensions typically <100 nm the spatial resolution of such a measurement would depend upon the tip itself, and would similarly be <100 nm. A TERS experiment usually involves focusing the excitation laser beam through standard microscope objectives, to yield a diffraction limi
