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arXiv · 2205.07329

Near-field Probing of Optical Superchirality for Enhanced Bio-detection

Victor Tabouillot·Rahul Kumar·Paula L. Lalaguna·Maryam Hajji·Rebecca Clarke·Affar Karimullah·Andrew R. Thomson·Andrew Sutherland·Nikolaj Gadegaard·Shun Hashiyada·Malcolm Kadodwala
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Abstract

Nanophotonic platforms in theory uniquely enable < femtomoles of chiral biological and pharmaceutical molecules to be detected, through the highly localised changes in the chiral asymmetries of the near-fields that they induce. However, current chiral nanophotonic based strategies are intrinsically limited because they rely on far-field optical measurements that are sensitive to a much larger near-field volume, than that influenced by the chiral molecules. Consequently, they depend on detecting small changes in far-field optical response restricting detection sensitivities. Here we exploit an intriguing phenomenon, plasmonic circularly polarised luminescence (PCPL), which is an incisive local probe of near-field chirality. This allows chiral detection of monolayer quantities of a de novo designed peptide, which is not achieved with a far-field response. Our work demonstrates that by leveraging the capabilities of nanophotonic platforms with the near-field sensitivity of PCPL, optimal biomolecular detection performance can be achieved, opening new avenues for nanometrology.

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Victor Tabouillot, Rahul Kumar, Paula L. Lalaguna, Maryam Hajji, Rebecca Clarke, Affar Karimullah, Andrew R. Thomson, Andrew Sutherland, Nikolaj Gadegaard, Shun Hashiyada, Malcolm Kadodwala. 2022-05-15. Near-field Probing of Optical Superchirality for Enhanced Bio-detection. https://doi.org/10.1021/acsphotonics.2c01073

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