A surface enhanced Raman spectroscopy (SERS) probe apparatus and a method of SERS probing employ Raman-active surfaces of a plurality of nanoscale field concentrator (NFC) structures at a terminal end of an optical fiber. The SERS probe apparatus includes an optical fiber having an optical path and a terminal end that terminates the optical path. The SERS probe apparatus further includes a plurality of NFC structures and nanoparticles on surfaces of the plurality of NFC structures. First ends of the NFC structures are adjacent to the terminal end of optical fiber. The nanoparticles are Raman active to an analyte.