Rapid Detection of Biological and Chemical Contaminants in Water with Evanescent field Coherent-Surface-Enhanced Raman Spectroscopy

A novel sensor based upon Coherent-Surface-Enhanced Raman scattering (CSERS) is being proposed for rapid detection of biological and chemical contaminants in water. The main characteristic of this sensor is a periodic array of metal nanoparticles or nanoshells deposited on the surface of an optical fiber waveguide. The nanoparticles/nanoshells will be deposited and immobilized in a periodic array by nanosphere lithography.This single fiber will transport the exciting laser radiation by the total internal reflection. The evanescent field at the interface (fiber/water) will interact with biological and chemical contaminant molecules adsorbed onto or near the surface of the metal nanoparticles producing the Raman shifted signal coherently amplified by the propagating coherent surface plasmons. These CSERS signals will enter the waveguide and be directed to a spectrometer. The sensor will work as an attached device to a normal Raman identification system developed by Senspex. This will turn a normal Raman system into a CSERS system.