Wavefront-modified vector beams for THz cornea spectroscopy

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Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2023-11-14

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Mcode

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Language

en

Pages

14

Series

Optics Express, Volume 31, issue 24, pp. 40293-40307

Abstract

Terahertz spectroscopy is a promising method to diagnose ocular diseases, where the cornea is typically imaged by Gaussian beams. However, the beam’s mismatch with the cornea’s spherical surface produces a 5-10 % error in analysis. We investigate cornea spectroscopy with wavefront-modified vector beams, reducing the original analysis error to less than 0.5 %. Vector beams are synthesized by our developed 3D Angular Spectrum Method expanded to vector spherical harmonic presentation, allowing wavefront modification and scattering analysis from 100-layer cornea models. We show that wavefront-modified spherical vector beams possess increased accuracy and non-sensitive focusing on cornea spectroscopy compared to the Gaussian beams. Additionally, we investigate wavefront-modified cylindrical vector beams, which show frequency-dependent scattering power arising from s- and p-polarizations. As a result, these beams are unsuitable for cornea spectroscopy, although they have potential for optical force applications. Wavefront-modified vector beams can be applied to spherical target spectroscopy and optical force applications, such as medicine, medical imaging, and optical tweezers.

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Keywords

Cornea spectroscopy, Mie scattering, electromagnetism

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Citation

Lamberg, J, Tamminen, A, Taylor, Z & Baggio, M 2023, ' Wavefront-modified vector beams for THz cornea spectroscopy ', Optics Express, vol. 31, no. 24, pp. 40293-40307 . https://doi.org/10.1364/OE.494460