Abstract: A species-specific metal clad segment on a waveguide, including a planar waveguide, allows controlled light leakage of light propagating through the waveguide by total internal reflection, to measure refractive index and identify chemical species. A waveguide sensor is designed for a particular chemical species by selecting a metal clad with an affinity for the species and by matching the refractive indices of the waveguide body, clad, metal clad segment and chemical species. Dual or multiple measurement methods use a pair or multiple metal clad segments of different specificity. The metal clad segment may include another material to provide a suitable refractive index while having the desired affinity for the chemical species or to provide a catalyst to react the species to form a reaction product which is more readily detected.

Abstract: Single or multi-cell reservoir sensors with single illumination sources and one or more detectors per cell unit have an arrangement whereby a gaseous, vapor or liquid sample enters the cell body and interacts with a sensing solution to detect and quantify a given species. Entrance of the sample into the sensor is through an opening in the cell body which may be covered with a membrane to contain the sensing reagent and to presort the species entering the cell. Reservoir cells can be used with organic, inorganic or biochemical sensing materials. A variety of sensors as alcohol, drugs of abuse, organic halides, cyanide and inorganic ions are provided.