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Author Spotlight: Fabrication of a Low-Cost, Fiber-Coupled, and Air-Spaced Fabry-Pérot Etalon
Published on: February 3, 2023
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Design of a sensitive uncooled thermal imager based on a liquid crystal Fabry-Perot interferometer
Applied Optics
|November 22, 2018
Summary
Researchers enhanced liquid crystal (LC) transducer sensitivity for uncooled thermal imaging. An etalon structure significantly boosts temperature-dependent intensity changes, improving thermal sensor performance.
Area of Science:
- Optics and Photonics
- Materials Science
- Infrared Technology
Background:
- Microbolometers are the leading technology for uncooled thermal imaging.
- Liquid crystal (LC) transducer pixels offer comparable sensitivity but can be improved.
Purpose of the Study:
- To investigate an etalon structure for increasing LC transducer sensitivity.
- To design and numerically evaluate an LC resonant cavity between dielectric mirrors.
Main Methods:
- Proposed a detailed design for an LC resonant cavity structure.
- Performed numerical and analytical calculations for a 470 nm thick LC pixel.
- Measured the transmission of visible light through the etalon, independent of IR sensor thermal contact.
Main Results:
- The etalon-based device demonstrated a 26-fold increase in temperature-dependent transmitted intensity change compared to direct retardation measurement.
- This indicates significantly enhanced sensitivity for the resonant structure.
Conclusions:
- An etalon structure offers a substantial improvement in LC transducer sensitivity for thermal imaging.
- Dielectric mirror materials, cavity dimensions, and process tolerances are key factors affecting device sensitivity.
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