Paper
7 March 2024 An electrically controlled liquid-crystal (LC) interference filter by light orientation for infrared multispectral imaging
Kewei Liu, Mao Ye, Zhe Wang, Xinyu Zhang
Author Affiliations +
Proceedings Volume 13084, MIPPR 2023: Multispectral Image Acquisition, Processing, and Analysis; 1308404 (2024) https://doi.org/10.1117/12.2691244
Event: Twelfth International Symposium on Multispectral Image Processing and Pattern Recognition (MIPPR2023), 2023, Wuhan, China
Abstract
This paper presents an electrically controlled liquid-crystal (LC) interference filter in the infrared multispectral imaging system. Based on the theory of multi-beam interference, the proposed structure utilizes a pair of parallel flat plates with a reflectivity of ~95% to form a Fabry-Perot (FP) cavity, realizing constructive interferences and destructive interferences in specific wavelengths for incident infrared broad-spectra. The filtering performance of the proposed structure can be controlled by incorporating electrode layers based on the electro-optical properties of LC. We simulate the filtering characteristics of the proposed structure according to the elastic continuum theory of LC. Then the zinc selenide (ZnSe)-based LC filter with a preset cavity depth of 50 μm was fabricated with light orientation instead of the conventional friction orientation method. An infrared spectra test system was built to measure the performance of the fabricated interference filter. The experimental results successfully demonstrate the filtering characteristics covering three important infrared window bands in accordance with the simulated results by applying different root mean square (RMS) voltages. Also, the fabricated filter brings a sharper transmission peak waveform in a higher frequency infrared band. The proposed filter has a low cost and weight and is easy to install, laying the foundation for developing full-wave infrared multispectral imaging systems.
© (2024) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Kewei Liu, Mao Ye, Zhe Wang, and Xinyu Zhang "An electrically controlled liquid-crystal (LC) interference filter by light orientation for infrared multispectral imaging", Proc. SPIE 13084, MIPPR 2023: Multispectral Image Acquisition, Processing, and Analysis, 1308404 (7 March 2024); https://doi.org/10.1117/12.2691244
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KEYWORDS
Liquid crystals

Infrared radiation

Tunable filters

Infrared imaging

Molecules

Transmittance

Multispectral imaging

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