Fig. 1
From: Tip-enhanced Raman spectroscopy: principles and applications

Schematic diagram of a TERS set-up. A schematic diagram illustrating the principle of AFM-TERS in transmission mode. The LSP resonance at the tip-apex between the tip-LSPs and laser-photons enhances and confines the EM field resulting in the enhancement of Raman signal from the analyte molecules in the immediate vicinity of the tip-apex