World Precision Instruments, Inc.

Su-Yi Liu

Harry Fein

Diping Che

A gas or vapor permeable optical fiber waveguide with a liquid core is employed as a probe for the detection or measurement of a chemical specie of interest by filling the waveguide core region with a reagent liquid which undergoes a change in an optical characteristic thereof when exposed to the chemical specie and then inserting the filled waveguide into an environment in which the chemical specie may be present. The chemical specie, if present, will permeate through the waveguide wall and react with or be absorbed in the core liquid. Sensitivity is enhanced by controlling the pressure differential across the waveguide wall and/or by shaping the waveguide to enlarge the surface area. When the reaction generates light, the devices which detect that light will be shaped and disposed to maximize the collection thereof.

Chemical sensing techniques employing liquid-core optical fibers

The chemical properties of an aqueous liquid, the liquid comprising a solvent having an index of refraction which is the same as or closely approaches that of water, are determined by Raman spectroscopy wherein a sample of the liquid is delivered into an optical waveguide. The waveguide is in the form of a capillary having a reflective surface defined by a material having a refractive index of less than 1.33. Excitation light is transmitted axially into the liquid at an end of the waveguide. The excitation light is transmitted the length of the waveguide, by reflection from the reflective surface, causing the fluid to emit Raman spectra. The Raman spectra is transmitted along the waveguide, collected and delivered to a spectrometer.

Long capillary waveguide raman cell

Water or some other aqueous fluid is employed as the light transmitting medium of a liquid core fiber-optic waveguide cell by employing, to define the core region, a waveguide vessel having an exterior coating composed of a material having a refractive index of less than 1.33. The light conducting channel defined by the aqueous fluid filled core may be a capillary or other suitably shaped vessel.

Growing community of inventors

Sarasota, FL, United States of America

Su-Yi Liu