Fano resonance-assisted all-dielectric array for enhanced near-field optical trapping of nanoparticles
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Near-field optics can overcome the diffraction limit by creating strong optical gradients to enable the trapping of nanoparticles. However, it remains challenging to achieve efficient, stable trapping without heating and thermal effects. Dielectric structures have been used to address this issue but usually offer weak trap stiffness. In this work, we exploit the Fano resonance effect in an all-dielectric quadrupole nanostructure to realize a 20-fold enhancement of trap stiffness, compared to the off-resonance case. This enables a high effective trap stiffness of 1.19 fN/nm for 100 nm diameter polystyrene nanoparticles with 4.2 mW/μm2 illumination. Furthermore, we demonstrate the capability of the structure to simultaneously trap two particles at distinct locations within the nanostructure array.
Conteduca , D , Khan , S N , Ruiz , M A M , Bruce , G D , Krauss , T F & Dholakia , K 2023 , ' Fano resonance-assisted all-dielectric array for enhanced near-field optical trapping of nanoparticles ' , ACS Photonics , vol. Articles ASAP . https://doi.org/10.1021/acsphotonics.3c01126
Copyright © 2023 The Authors. Open Access. Published by American Chemical Society. This publication is licensed under a Creative Commons Attribution licence, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/).
DescriptionFunding: This work was supported by the UK Engineering and Physical Sciences Research Council (EP/P030017/1), and the Australian Research Council (grant DP220102303).
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