The working principle of TERS involves a combination of localized surface plasmon resonance (LSPR) and the Raman scattering effect. Here’s a simplified explanation: 1. Tip-Sample Interaction: A sharp metallic tip is positioned close to the sample surface, typically within a few nanometers. 2. Laser Excitation: A laser is focused onto the tip-sample junction. The metallic tip enhances the electromagnetic field in its vicinity due to LSPR. 3. Raman Scattering: Molecules near the tip experience an enhanced electromagnetic field, resulting in a significantly amplified Raman signal. 4. Detection: The enhanced Raman signal is collected and analyzed, providing detailed chemical information about the sample at the nanoscale.
