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A Broadly Tunable Surface Plasmon-Coupled Wavelength Filter for Visible and Near Infrared Hyperspectral Imaging

Zalavadia, Ajaykumar
http://orcid.org/0000-0002-4468-3865
http://rave.ohiolink.edu/etdc/view?acc_num=csu1522253688346498

Abstract Details

2018, Doctor of Philosophy in Clinical-Bioanalytical Chemistry, Cleveland State University, College of Sciences and Health Professions.
Hyperspectral imaging is a set of techniques that has contributed to the study of advanced materials, pharmaceuticals, semiconductors, ceramics, polymers, biological specimens, and geological samples. Its use for remote sensing has advanced our understanding of agriculture, forestry, the Earth, environmental science, and the universe. The development of ultra-compact handheld hyperspectral imagers has been impeded by the scarcity of small widefield tunable wavelength filters. The widefield modality is preferred for handheld imaging applications in which image registration can be performed to counter scene shift caused by irregular user motions that would thwart scanning approaches. In the work presented here an electronically tunable widefield wavelength filter has been developed for hyperspectral imaging applications in the visible and near-infrared region. Conventional electronically tunable widefield imaging filter technologies include liquid crystal-based filters, acousto-optic tunable filters, and electronically tuned etalons; each having its own set of advantages and disadvantages. The construction of tunable filters is often complex and requires elaborate optical assemblies and electronic control circuits. I introduce in the work presented here is a novel widefield tunable filter, the surface plasmon coupled tunable filter (SPCTF), for visible and near infrared imaging. The SPCTF is based on surface plasmon coupling and has simple optical design that can be miniaturized without sacrificing performance. The SPCTF provides diffraction limited spatial resolution with a moderately narrow nominal passband (<10 nm) and a large spurious free spectral range (450 nm-1000 nm). The SPCTF employs surface plasmon coupling of the π-polarized component of incident light in metal films separated by a tunable dielectric layer. Acting on the π-polarized component, the device is limited to transmitting 50 percent of unpolarized incident light. This is higher than the throughput of comparable Lyot-based liquid crystal tunable filters that employ a series of linear polarizers. In addition, the SPCTF is not susceptible to the unwanted harmonic bands that lead to spurious diffraction in Bragg-based devices. Hence its spurious free spectral range covers a broad region from the blue through near infrared wavelengths. The compact design and rugged optical assembly make it suitable for hand-held hyperspectral imagers. The underlying theory and SPCTF design are presented along with a comparison of its performance to calculated estimates of transmittance, spectral resolution, and spectral range. In addition, widefield hyperspectral imaging using the SPCTF is demonstrated on model sample.
John Turner, II, PhD (Committee Chair)
David Ball, PhD (Committee Member)
Mekki Bayachou, PhD (Committee Member)
Baochuan Guo, PhD (Committee Member)
Petru Fodor, PhD (Committee Member)
151 p.
Analytical Chemistry; Chemistry; Electromagnetism; Optics; Physics
Surface Plasmon; Tunable Filter; Spectral Imaging; Hyperspectral Imaging; Visible; Near Infrared; Short Range Propagating Polariton; Long Range Propagating Polariton; SPCTF; Surface Plasmon-Coupled Tunable Filter;

Recommended Citations

Citations

  • Zalavadia, A. (2018). A Broadly Tunable Surface Plasmon-Coupled Wavelength Filter for Visible and Near Infrared Hyperspectral Imaging [Doctoral dissertation, Cleveland State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=csu1522253688346498

    APA Style (7th edition)

  • Zalavadia, Ajaykumar. A Broadly Tunable Surface Plasmon-Coupled Wavelength Filter for Visible and Near Infrared Hyperspectral Imaging. 2018. Cleveland State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=csu1522253688346498.

    MLA Style (8th edition)

  • Zalavadia, Ajaykumar. "A Broadly Tunable Surface Plasmon-Coupled Wavelength Filter for Visible and Near Infrared Hyperspectral Imaging." Doctoral dissertation, Cleveland State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=csu1522253688346498

    Chicago Manual of Style (17th edition)

csu1522253688346498
578
© 2018, some rights reserved.Creative Commons License A Broadly Tunable Surface Plasmon-Coupled Wavelength Filter for Visible and Near Infrared Hyperspectral Imaging by Ajaykumar Zalavadia is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by Cleveland State University and OhioLINK.