A stimulated Raman scattering (SRS) spectrometer for real-time, high-resolution molecular analysis of gases is based on two hollow-core fibres illuminated by a single high-power, short-pulse laser pump. The first fibre is prefilled with high-concentration target gases. Interaction of each target gas inside the first fibre, with the laser pump, generates Raman signals corresponding to the target gases. The combined beam of the Raman signals and the pump laser beam is directed into the second fibre containing the measured target gases. Interaction of each target gas with the combined beam generates the Stimulated Raman Growth (SRG), i.e., amplification of the Raman signal, which is proportional to the corresponding target gas concentration. A receiver subsystem receives the beam from the second fibre, spectrally separates it to wavelengths corresponding to each target gas, extracts the SRG value corresponding to each target gas and calculates the concentration of each target gas.

A method for assessing a cancer status of biological tissue includes the steps of: obtaining a Raman spectrum indicating a Raman spectroscopy response of the biological tissue, the Raman spectrum captured using a fiber-optic probe of a fiber-optic Raman spectroscopy system; inputting the Raman spectrum into a boosted tree classification algorithm of a computer program, and using the boosted tree classification algorithm for comparing, in real-time, the captured Raman spectrum to reference data and assessing the cancer status of the biological tissue based on said comparison, the reference data being previously determined based on a set of reference Raman spectra indicating Raman spectroscopy responses of reference biological tissues wherein each of the reference biological tissues is associated with a known cancer status; and generating a real-time output indicating the assessed cancer status of the biological tissue,

A solution is provided comprising boron nitride nanotubes (BNNTs) in a liquid solvent. An optical waveguide, such as an optical fiber, is contacted with the solution so as to form a layer of the solution supported on at least a portion of the optical waveguide. The liquid solvent is then removed from the layer of the solution supported on the optical waveguide in order to form a coating of the BNNTs on the optical waveguide. Further provided is a BNNT coated optical waveguide for use as a sensor.

A fiber optic temperature probe is disclosed. The fiber optic temperature probe includes a probe shaft containing an optical fiber. An optical temperature sensor element is coupled to the probe shaft and configured to be excited by light from the optical fiber and emit light back to the optical fiber. A thermally conductive plate is coupled to the probe shaft and interfaces with the optical temperature sensor element. Baffling extends from the probe shaft and surrounds the edges of the thermally conductive plate.

A fiber-optic sensing apparatus, system, and method for characterizing at least one metal ion in a solution are provided. The sensing apparatus includes a fiber-optic sensor and a controller. The sensor includes an optical fiber with tilted grating in its core, and includes a conductive and surface plasmon resonance (SPR)-active coating assembly that allows the sensor to also serve as an electrochemical working electrode. The controller is electrically connected with the sensor, configured to provide an adjustable potential such that when the coating assembly is in contact with the solution, redox reactions of each of the at least one metal ion occur on an outer surface thereof, resulting in a detectable change of the surface plasmon waves generated in the fiber-optic sensor. Based on the change thus detected, identities and/or concentration of the at least one metal ion in the solution can be determined with high accuracy and sensitivity.

Embodiments of the present invention include a system and method for detecting or sensing damage within a target material, as well as related devices. In some embodiments, a damage sensing system including a target material, an optical fiber embedded into the target material, where the optical fiber has an outer surface running the length of the optical fiber, a photosensitive receiver, and a triboluminescent coating coated on the optical fiber.

Corrosion detection systems and methods can include at least one fiber optic cable embedded in a material having at least two layers. Two of the layers can define an interface, and the fiber optic cable can be embedded at the interface. Each fiber optic cable can have a plurality of Fiber Bragg Gratings (FBG's) formed therein at predetermined intervals. Each FBG can have a preselected geometry that can only allow a predetermined light wavelength to pass therethrough. A light source for inputting light and a photodetector can be connected to opposite exposed ends of the fiber optic cable. As corrosion occurs near an FBG, it experiences mechanical strain, which can further cause a slightly different wavelength to pass through the fiber optic cable. The change in in wavelength can be detected by the photodiode as being indicate of corrosion occurring at the site near the FBG.

A method of making an optical fiber-based sensor includes providing an optical fiber, and providing a sensing or protection layer on a surface of the optical fiber by an atomic layer deposition (ALD) process.

A pH photothermal spectrometer includes a container that receives an analyte medium and pH-sensitive chromophore. An excitation fiber and optical thermometer are disposed in the container. The optical thermometer include a light receiver disposed on a temperature detector fiber.

A sensing system for monitoring a composition of a downhole fluid in a well, where the sensing system includes: a light source, an optical waveguide, an evanescent field sensing element that is indirect contact with a downhole fluid, and a detector. The light source is operable for emitting a beam and includes a frequency comb generator configured to modify at least a portion of the beam into a sensing comb beam. The evanescent field sensing element provides attenuated internal reflection of the sensing comb beam at the interface between the evanescent field sensing element and the downhole fluid, and the portion of the sensing comb beam interacts with the fluid to form at least a portion of an interacted beam. The detector obtains a spectral distribution of the interacted beam.