Sensing and/or protection layers for optical fiber-based sensors using atomic layer deposition synthesis on optical fibers
Inventors
Ohodnicki, JR., Paul Richard • Lee, Jung-Kun • LIU, Yulin • Wright, Ruishu • Lu, Fei • Wuenschell, Jeffrey
Assignees
US Department of Energy • University of Pittsburgh
Publication Number
US-11782210-B2
Publication Date
2023-10-10
Expiration Date
2042-04-07
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Abstract
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.
Core Innovation
The invention relates to a method of making an optical fiber-based sensor by providing a sensing or protection layer on a surface of the optical fiber using an atomic layer deposition (ALD) process. The sensing or protection layer consists of a nanometer scale thin film, which may be an oxide such as a refractory oxide including TiO2, ZrO2, or Al2O3. The layer can also include nanoparticles such as plasmonic nanoparticles or core-shell quantum dot nanoparticles.
The method leverages ALD to deposit high-quality, uniform, conformal, nanometer-scale thin films directly onto optical fibers, which is uniquely suited for coating optical fiber-based sensors due to the non-directional nature of ALD and its scalable processing. This enables the creation of stable sensing and protective layers for harsh environments and high temperature applications, enhancing sensing responses, optical transmission stability, and resistance against long-term degradation in nonambient gas atmospheres.
The problem being solved addresses the limitations of conventional electrical-based sensor instrumentation, which suffers from instability and deployment challenges at extreme temperatures and in non-ambient chemical environments. Optical fiber-based sensors show promise for high-temperature sensing but require improved sensing layers that are stable and functional at elevated temperatures. This invention meets the need for functional, stable sensing and protection layers on optical fibers capable of use in high temperature environments, enabling improved sensing performance such as reversible hydrogen detection, crystallization-driven optical absorption changes, and suitability for harsh chemical atmospheres.
Claims Coverage
The patent contains one independent method claim focusing on forming an optical fiber-based sensor with a sensing or protection layer deposited by atomic layer deposition and subsequent crystallization. The main inventive features extracted from the claim are as follows.
Formation of sensing or protection layer by atomic layer deposition
A method comprising providing an optical fiber and depositing a sensing or protection layer on its surface via an atomic layer deposition (ALD) process, where the layer includes a nanometer scale thin film comprising an oxide.
Crystallization of oxide layer to modify optical absorption
The method includes causing crystallization of the oxide layer by heating above a critical temperature of 400° C.-500° C., resulting in an irreversible change in optical absorption of the sensing or protection layer.
The inventive features together cover a method of forming a nanometer-scale oxide film on an optical fiber by ALD and subsequently crystallizing it through controlled heating to achieve an irreversible optical absorption change, thereby enhancing sensor functionality and stability for high temperature applications.
Stated Advantages
ALD provides uniform, conformal coatings that enhance stability of sensing responses and optical transmission over time in challenging, high temperature environments.
Coating refractory oxides such as TiO2, ZrO2, and Al2O3 improves thermal and chemical stability, enabling sensors to withstand harsh conditions.
Nanoparticle incorporation (e.g., plasmonic, core-shell quantum dots) allows enhanced sensing responses.
The method enables reversible and strong hydrogen sensing responses at elevated temperatures up to 800° C.
The conformal nature of ALD coatings uniquely suits optical fiber sensor coating requirements, allowing scalable and precise thin film control.
Documented Applications
In-situ monitoring of elevated temperature gas stream chemistry at temperatures greater than approximately 500° C.
Applications including solid oxide fuel cells, electrolyzers, reversible solid oxide fuel cell/electrolyzer systems, and chemical process reactors.
High temperature optical fiber-based sensing platforms employing evanescent wave absorption spectroscopy.
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