tip-enhanced Raman spectroscopy 

Initialism: TERS
https://doi.org/10.1351/goldbook.08699
Measurement method of Raman spectroscopy combining surface-enhanced Raman spectroscopy and scanning using an atomic force microscope or scanning tunnelling microscope to give complementary maps of a surface.
Source:
PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 767 (https://doi.org/10.1515/pac-2019-0203)