Single-fibre surface-enhanced Raman sensors with angled tips

Abstract

Single-fibre surface-enhanced Raman sensors were prepared by depositing rough metal films at the tips of optical fibres. Different deposition techniques such as slow evaporation of metal island films and vacuum deposition of metal films over nanoparticles or on pre-roughened surfaces were applied and compared. The superposition of surface Raman spectra from the tips with Raman spectra of the fibre core made maximum enhancements necessary for the construction of long fibre sensors. The enhancement was improved significantly by altering the tip geometry. Angled polishing has enhanced the SERS intensity by up to a factor of 6. The intensity increases monotonically with increase in the angle, reaching its maximum value at the largest prepared angle of 40°. Copyright © 2000 John Wiley & Sons, Ltd.