Enhancement of the signal-to-noise ratio in fiber-optics based SERS detection by rough-cutting the end surface.

Fiber-optics based surface-enhanced Raman scattering (FO-SERS) has an unique advantage of being able to remotely detect analyte molecules because the fiber length can be adjusted as desired. However, the Raman signal of the fiber-optic material is so strong that it is an important challenge in utilization of optical fiber for remote SERS sensing. In this study, we found that the background noise signal was greatly reduced by ca. 32% compared to conventional fiber-optics with a flat surface cut. To confirm the feasibility of FO-SERS detection, silver nanoparticles labeled with 4-fluorobenzenethiol were attached onto the end surface of an optical fiber to form a SERS-signaling substrate. The SERS intensity from the fiber-optics with a roughened surface as SERS substrate was increased significantly with respect to signal-to-noise ratio (SNR) values compared to optical fibers with flat end surface. This result implies that the fiber-optics with roughened surface could be used as an efficient alternative for FO-SERS sensing platform.