SERS Fiber Optic Probes

We are using Surface Enhanced Raman Scattering (SERS) to develop a fiber optic probe for monitoring groundwater contamination. Attaching a molecule to a SERS surface produces a million fold enhancement of the Raman signal. Our approach is to fabricate a SERS surface at the fiber tip and attach indicators to the silver SERS surface. The SERS surface is fabricated by roughening the end of the optical fiber with polishing paper and vacuum depositing silver over the roughened fiber tip. We irreversibly bind the indicators by modifying the acid group of the indicator with a thiol containing species. The thiol anchors the indicator to the silver surface and forms an inert, robust coating.