A sensor for performing surface enhanced Raman spectroscopy (SERS) includes a sensor body having a throughbore; a window mounted to the sensor body that is coterminous with the throughbore; surface enhanced Raman scattering structure mounted to the window; an optical energy source for generating an optical excitation signal; a first optical fiber mounted in the throughbore for directing the optical excitation signal through the surface enhanced Raman scattering (SERS) structure; a second optical fiber mounted in the throughbore for receiving primary Raman emissions generated when an analyte in contact with the surface enhanced Raman scattering structure is irradiated by the optical excitation signal; and an optical detector for generating an optical signal representing the primary Raman emissions.

A system for determining gas compositions includes a probe, inserted into a source of gaseous material, the probe having a gas permeable sensor tip and being capable of sending and receiving light to and from the gaseous material, a sensor body, connected to the probe, situated outside of the source and a fiber bundle, connected to the sensor body and communicating light to and from the probe. The system also includes a laser source, connected to one portion of the fiber bundle and providing laser light to the fiber bundle and the probe a Raman spectrograph, connected to another portion of the fiber bundle, receiving light from the probe and filtering the received light into specific channels and a data processing unit, receiving and analyzing the received light in the specific channels and outputting concentration of specific gas species in the gaseous material based on the analyzed received light.

A sensor for performing surface enhanced Raman spectroscopy comprises: a) a sensor body having a throughbore; an optical energy source for generating an optical excitation signal; b) a surface enhanced Raman scattering structure that is mounted to the sensor body through which the optical excitation signal is directed for irradiating an analyte, whereupon the analyte generates primary Raman emissions in response to being irradiated by the optical excitation signal, and wherein the surface enhanced Raman scattering structure generates secondary Raman emissions when irradiated by the optical excitation signal; c) an optical detector for generating an output signal that represents the spectral characteristics of the primary and secondary Raman emissions in response to receiving the primary and second Raman emissions; and d) a processor for substantially filtering the secondary Raman emission from the primary Raman emissions and for generating an output signal representing the analyte.

A glass fiber (22) has a core (24) provided with Raman laser effect particles (28) embedded in a glass matrix (30), with glass cladding (26) around the core. The refractive index of the glass matrix (30) is matched to that of the Raman laser effect particles (28) so as to avoid scattering. It is not necessary to have a single crystal of Raman laser material to create a laser effect in the glass fiber. A length of fiber in the order of meters or tens of meters can produce optical laser light. It is possible to have a single fiber (22) emit laser light at different frequencies due to Stokes and Anti-Stokes emissions. A simple laser device can therefore produce several colors of laser beams.

A chemical detection sensor system comprises a support structure; multiple SERS chemical detection sensors supported by the support structure; multiple chemical reaction sensors, wherein each of the chemical reaction sensors is disposed for undergoing a state change in response to an occurrence of a chemical reaction at one of the SERS chemical detection sensors; a processor supported by the support structure for recording data representing occurrence of a chemical reaction at any of the chemical detection sensors in response to sensing the state change; and a power source for energizing the processor.