Li, Kezheng, Martins, Augusto, Bohora, Sanket et al. (3 more authors) (2023) Hybrid Metalens for Miniaturised Ultraviolet Fluorescence Detection. Advanced Optical Materials. 2300852. ISSN 2195-1071
Abstract
The advantages of metalenses to enable miniaturized systems have been well established, especially in the visible and infrared wavelength regimes. The ultraviolet (UV) presents a final frontier because feature size scales as the wavelength, so realizing a large size metalens with a high numerical aperture (NA) in the UV is a major challenge. Here, a single-layer, thin-film (450 nm) hybrid metalens with an NA of 0.9 and a diameter of 6.2 mm is presented. By combining a Fresnel lens and optimised binary gratings, the well-known shadowing effect of Fresnel lenses at high NA is avoided while being able to realize a large area lens. It is demonstrated that the combination of high NA and large area affords efficient detection of tryptophan-like fluorescence, which is a well-studied proxy for water contamination with faecal coliforms. The detection of tryptophan at levels better than 1 ppb, which corresponds to the low-risk category for drinking water according to the World Health Organization (WHO), is shown. It is also confirmed that the hybrid metalens fluorescence collection efficiency is 3.5 times higher than a high NA plano-convex lens used in state-of-the-art fluorometers, which demonstrates that the versatile metalens approach opens up new opportunities in the UV.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2023 The Authors. |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Physics (York) |
Depositing User: | Pure (York) |
Date Deposited: | 08 Sep 2023 08:40 |
Last Modified: | 25 Oct 2024 00:15 |
Published Version: | https://doi.org/10.1002/adom.202300852 |
Status: | Published online |
Refereed: | Yes |
Identification Number: | 10.1002/adom.202300852 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:203194 |
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Description: Hybrid Metalens for Miniaturised Ultraviolet FluorescenceDetection
Licence: CC-BY 2.5