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Proceedings Paper

Nanoparticle trapping and characterization with open microcavities (Conference Presentation)
Author(s): Aurelien Trichet; Philip R. Dolan; Dean James; Gareth M. Hughes; Claire Vallance; Jason M. Smith

Paper Abstract

Thanks to their low mode volume and high finesse, optical microresonators have emerged as a promising avenue to detect and measure properties of single nanoparticles such as viruses or gold nanoparticles. Thanks to the resulting electromagnetic field enhancement, small nanoparticles, viruses and even single proteins have been trapped in hollow resonators such as photonic crystals or plasmonic tweezers. Such trapping devices with sensing capabilities are on the verge of finding powerful applications in interdisciplinary science. However, the quest for a candidate bringing together in-situ detection, trapping and multiple quantitative measurements of the particle properties supported by a comprehensive understanding still remain elusive. In this work, we show that open-access microcavities fulfil these criteria. Such resonators are made up of two micro-mirrors facing each other separated by a fluid medium in which nanoparticles can diffuse. We have recorded the cavity mode spectra while nanoparticles were optically trapped. Our results demonstrate that these microcavities can be used as optical tweezers with in-situ force calibration and nanoparticle sensing capabilities, including measurement of shape anisotropy. The shift in cavity mode wavelength during a trapping event provides information on both the nanoparticle and trap properties, as well as on the trapping force holding the particle in the trap. We are able to determine in real-time the nanoparticle polarizability, i.e. its optical response to an electromagnetic field, its coefficient of friction and characterize its shape anisotropy. The high level of control in this device makes it a robust analytical tool for real-time nanoparticle characterisation and monitoring.

Paper Details

Date Published: 2 May 2017
PDF: 1 pages
Proc. SPIE 10081, Frontiers in Biological Detection: From Nanosensors to Systems IX, 100810H (2 May 2017); doi: 10.1117/12.2251466
Show Author Affiliations
Aurelien Trichet, Univ. of Oxford (United Kingdom)
Philip R. Dolan, Univ. of Oxford (United Kingdom)
Dean James, Univ. of Oxford (United Kingdom)
Gareth M. Hughes, Univ. of Oxford (United Kingdom)
Claire Vallance, Univ. of Oxford (United Kingdom)
Jason M. Smith, Univ. of Oxford (United Kingdom)

Published in SPIE Proceedings Vol. 10081:
Frontiers in Biological Detection: From Nanosensors to Systems IX
Amos Danielli; Benjamin L. Miller; Sharon M. Weiss, Editor(s)

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