Thermally emissive sensing materials for chemical spectroscopy analysis
Inventors
Poole, Zsolt • Ohodnicki, Paul R.
Assignees
Publication Number
US-9964494-B1
Publication Date
2018-05-08
Expiration Date
2036-05-20
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
A sensor using thermally emissive materials for chemical spectroscopy analysis includes an emissive material, wherein the emissive material includes the thermally emissive materials which emit electromagnetic radiation, wherein the electromagnetic radiation is modified due to chemical composition in an environment; and a detector adapted to detect the electromagnetic radiation, wherein the electromagnetic radiation is indicative of the chemical interaction changes and hence chemical composition and/or chemical composition changes of the environment. The emissive material can be utilized with an optical fiber sensor, with the optical fiber sensor operating without the emissive material probed with a light source external to the material.
Core Innovation
The present disclosure relates to thermally emissive materials for chemical spectroscopy analysis which emit electromagnetic radiation indicative of chemical interaction changes of a surrounding environment, without requiring external illumination to probe the material. The thermally emissive materials generate light from the thermal energy of the surrounding, and the light emitted by the thermally emissive materials is indicative of the chemical composition of the environment. An exemplary embodiment integrates thermally emissive sensing materials with an optical fiber platform in an evanescent sensor configuration, thereby allowing observation of environmentally characteristic thermal emission of a chosen material.
There is a need for sensors and monitoring schemes operable in high temperature and harsh environments, such as fossil-based power generation, industrial manufacturing, and aerospace, where temperatures can range from 500 to 1500 °C or more. Existing sensing technologies, especially in harsh environments, lack fast in-situ feedback capabilities. Optical-based sensing methodologies have advantages like lack of electrical wiring, reduced risk of sparking, and ability to perform broad wavelength interrogation, but typically require an external light source that increases cost and complexity. The invention addresses the problem of eliminating the need for an external light source by exploiting the inherent thermal emission of materials whose emission characteristics change with chemical composition of the environment.
The invention uses thermally emissive sensing materials which emit electromagnetic radiation modulated by changes in chemical composition of their environment. When integrated with optical fiber sensors, the need for probing with an external light source is eliminated, reducing cost and complexity. The emissive materials may be deposited on, coated on, or integrated with the optical fiber core, cladding, or other modifications like fiber Bragg gratings. Emissivity changes are observed with high isolation from the background by overlapping the emissive material near-field and optical fiber evanescent regions, enabling remote, distributed sensing of chemical composition in harsh, high-temperature environments.
Claims Coverage
The patent contains three independent claims covering optical fiber sensors and methods using thermally emissive materials for chemical spectroscopy analysis, with associated features and configurations.
Optical fiber sensor with distributed thermally emissive materials without external light source
An optical fiber sensor comprising emissive materials including TiO2, Pd—TiO2, and Au—TiO2 nanocomposites, perovskite oxide, and SrTiO3 or doped SrTiO3 which emit electromagnetic radiation modulated by chemical environment. The sensor includes a distributed optical fiber with a plurality of emissive materials each operating at different wavelengths and a detector detecting this radiation indicative of chemical interaction changes, operating without probing with an external light source.
Integration of emissive materials with optical fiber configurations for chemical composition detection
The emissive material is deposited on the fiber core or end-face, coated on the fiber, or integrated with the fiber core, cladding, or combination thereof to derive chemical composition information. The sensor can include dual detectors at opposite fiber ends to monitor outputs and spatial dependence, and the emissive materials interact with environment chemistry to provide altered emissivity observable via tunneling coupling through near-field and evanescent region overlap.
Method for chemical spectroscopy using thermally emissive materials and optical fiber without external light source
A method emitting radiation from thermally emissive materials responsive to thermal energy altered by chemical changes, with emissive materials including TiO2, Pd—TiO2, Au—TiO2 nanocomposites, perovskite oxides, and SrTiO3 or doped SrTiO3. The optical fiber sensor operates without probing with external light, includes a distributed fiber with multiple emissive materials at different wavelengths, and detects radiation indicative of chemical composition changes.
The claims cover sensors and methods utilizing thermally emissive materials integrated with optical fibers configured to detect chemical composition changes based on thermally induced electromagnetic radiation, eliminating the need for external light probing and enabling distributed, multiplexed, and spatially resolved sensing capabilities.
Stated Advantages
Elimination of the need for an external light source greatly simplifies optical sensor design and reduces cost.
Provides fast, in-situ chemical composition analysis in high-temperature, harsh environments up to and above 800 °C.
Compatibility with optical fiber based platforms facilitates remote and distributed sensing with high isolation from background interferences.
Enables simultaneous detection at multiple wavelengths and locations for spatially localized chemical sensing.
Reduces complexity and power consumption of optical sensors, enhancing reliability in harsh and high-temperature applications.
Documented Applications
High-temperature gas stream composition monitoring in power generation applications including turbines, combustion, solid oxide fuel cells, and gasification.
Monitoring exhausts of combustion processes in turbines and industrial manufacturing.
Chemical composition sensing in harsh and elevated temperature environments potentially including chemical reactors and furnaces.
Energy harvesting applications converting thermal energy to optical and electrical energy using thermally emissive materials coupled with photovoltaic cells.
Interested in licensing this patent?