A waveguide sensor system is provided. The system includes a light source and a waveguide formed from a light transmitting material. Light from the light source enters the waveguide at an input area and travels within the waveguide by total internal reflection to an analyte area and light to be analyzed travels within the waveguide from the analyte area by total internal reflection to an output area. An optical sensor is coupled to the output area and is configured to interact with the light to be analyzed. The system includes a plurality of pores located along the outer surface within the analyte area and formed in the light transmitting material of the waveguide, and the pores are configured to enhance light interaction with the analyte within the analyte area.

A system and method for determining concentration of a constituent of a sample fluid includes a flow cell with a light source emitting incident light to a proximal end thereof. Media disposed within the flow cell supports nanostructures that are substantially transparent in at least a portion of the incident light spectrum. The nanostructures adsorb or absorb the constituent to attain a concentration that is a multiple of the concentration of the constituent in the sample fluid. A sensor detects transmitted light exiting from the media, and generates outputs corresponding to a spectrum of the transmitted light. A processor captures the sensor outputs and compares the incident light spectrum to the transmitted light spectrum to generate an absorbance spectrum. The absorbance spectrum is used to calculate the concentration in the nanostructures, which is then used with the predetermined multiple to calculate the sample concentration.

A chemical sensor, including a porous optical waveguide. The loss or index of refraction, or both, of the porous waveguide is affected by the presence of one or more chemicals of interest.

A waveguide sensor system is provided. The system includes a light source and a waveguide formed from a light transmitting material. Light from the light source enters the waveguide at an input area and travels within the waveguide by total internal reflection to an analyte area and light to be analyzed travels within the waveguide from the analyte area by total internal reflection to an output area. An optical sensor is coupled to the output area and is configured to interact with the light to be analyzed. The system includes a plurality of pores located along the outer surface within the analyte area and formed in the light transmitting material of the waveguide, and the pores are configured to enhance light interaction with the analyte within the analyte area.

A method of detecting at least one of an analyte or a condition of a fluid within a subterranean formation includes operably coupling a radiation source to at least one optical fiber coupled to a sensor having optically sensitive materials including at least one of chromophores, fluorophores, metal nanoparticles, or metal oxide nanoparticles dispersed within an optically transparent permeable matrix material. The sensor is contacted within a wellbore with a fluid and the fluid is passed through at least a portion of the sensor. Electromagnetic radiation is transmitted from the radiation source through at least one optical fiber to the sensor and at least one of an absorbance spectrum, an emission spectrum, a maximum absorption intensity, or a maximum emission intensity of electromagnetic radiation passing through the sensor after contacting at least some of the optically sensitive materials with the fluid is measured. Additional methods of determining a concentration of hydrogen sulfide in a fluid within a subterranean formation and related downhole optical sensor assemblies are disclosed.

A system and method for determining concentration of a constituent of a sample fluid includes a flow cell with a light source emitting incident light to a proximal end thereof. Media disposed within the flow cell supports nanostructures that are substantially transparent in at least a portion of the incident light spectrum. The nanostructures adsorb or absorb the constituent to attain a concentration that is a multiple of the concentration of the constituent in the sample fluid. A sensor detects transmitted light exiting from the media, and generates outputs corresponding to a spectrum of the transmitted light. A processor captures the sensor outputs and compares the incident light spectrum to the transmitted light spectrum to generate an absorbance spectrum. The absorbance spectrum is used to calculate the concentration in the nanostructures, which is then used with the predetermined multiple to calculate the sample concentration.

A metal ion detection equipment and a metal ion detection method are provided. The metal ion detection equipment includes a porous silicon resonant cavity structure, an electrochemical device and a spectrum detecting device. A sample solution permeates into the porous silicon resonant cavity structure. A to-be-detected metal ion of the sample solution in the porous silicon resonant cavity structure is reduced into a to-be-detected metal by the electrochemical device. The spectrum detecting device detects a spectral variation of a reflective light from the porous silicon resonant cavity structure.

A method of detecting at least one of an analyte or a condition of a fluid within a subterranean formation comprises operably coupling a radiation source to at least one optical fiber coupled to a sensor comprising optically sensitive materials including at least one of chromophores, fluorophores, metal nanoparticles, or metal oxide nanoparticles dispersed within an optically transparent permeable matrix material. The sensor is contacted within a wellbore with a fluid and the fluid is passed through at least a portion of the sensor. Electromagnetic radiation is transmitted from the radiation source through at least one optical fiber to the sensor and at least one of an absorbance spectrum, an emission spectrum, a maximum absorption intensity, or a maximum emission intensity of electromagnetic radiation passing through the sensor after contacting at least some of the optically sensitive materials with the fluid is measured. Additional methods of determining a concentration of hydrogen sulfide in a fluid within a subterranean formation and related downhole optical sensor assemblies are disclosed.

Disclosed is an optical sensor (1) for detecting a chemical species, including: a substrate (3); a mesoporous matrix (5) disposed on the substrate; a microporous matrix (7) disposed within the mesoporous matrix, the microporous matrix (7) including an indicator dye (9) dispersed therein, the indicator dye (9) exhibiting changes in its optical properties in response to the presence of the chemical species.

Devices, systems, and methods include a system comprising a substrate having a transparent portion, one or more reactants on a first surface of the transparent portion of the substrate, a light source, and a light collector. The light source may be configured to illuminate the one or more reactants through the transparent portion of the substrate and the light collector may be configured to collect light from the one or more reactants. The light from the one or more reactants may be collected from the reactants without the light from the reactants traveling through the substrate and/or may be collected from the reactants after the light from the reactants has passed through the substrate.