REMOTE FIBER OPTIC SENSOR FOR GASEOUS AND LIQUID ENVIRONMENT BASED ON SURFACE ENHANCED RAMAN SPECTROSCOPY (SERS)

THERE IS A UNIVERSAL NEED WITHIN THE DEFENSE-RELATED OPERATIONS FOR CHEMICAL SENSING. IN MOST CASES, THE FAVORABLE CONFIGURATION OF A SENSOR WOULD BE ONE IN WHICH THE DETECTOR (I.E., PROBE) WOULD OPERATE IN SITU AND PRODUCE INFORMATION ON CHEMICAL COMPOSITION IN REAL TIME WITH A HIGH LEVEL OF SENSITIVITY (PPB OR LESS). IT IS THE GOAL OF THE PROPOSED WORK TO DEVELOP A "UNIVERSAL" REMOTE SENSOR FOR ORGANIC AND INORGANIC COMPOUNDS IN BOTH THE GASEOUS AND LIQUID ENVIRONMENT. THE PROPOSED SENSOR WOULD BE BASED ON SURFACE ENHANCED RAMAN SPECTROSCOPY (SERS). THE SERS SIGNAL, WHICH CORRESPONDS TO VIBRATIONAL SPECTRA OF A MOLECULE ADSORBED ONTO A ROUGHENED METAL SUBSTRATE, IS OBTAINED FROM THE RAMAN SCATTERING OFF THE SUBSTRATE USING A VISIBLE LASER SOURCE. REMOTE SENSING WILL BE ACHIEVED USING OPTICAL FIBERS FOR EXCITING THE METAL SUBSTRATE, CONTAINED IN A PROBE HEAD, AND FOR RETURNING THE SCATTERED LIGHT TO THE DETECTOR. THE GOAL OF PHASE I IS THE DEMONSTRATION THAT SERS CAN BE USED AS A GAS PHASE SENSOR FOR ORGANIC GASES OR MIXTURES OF ORGANIC GASES. THE GOAL OF THE PHASE II PROGRAM IS TO DEVELOP A SERS FIBER OPTIC BASED "UNIVERSAL" SENSOR FOR ORGANIC AND INORGANICS IN BOTH THE GASEOUS AND LIQUID ENVIRONMENTS.