Rotational Doppler velocimetry to probe the angular velocity of spinning microparticles

Phillips, D. B., Lee, M. P., Speirits, F. C. , Barnett, S. M. , Simpson, S. H., Lavery, M. P. J., Padgett, M. J. and Gibson, G. M. (2014) Rotational Doppler velocimetry to probe the angular velocity of spinning microparticles. Physical Review A: Atomic, Molecular and Optical Physics, 90(1), 011801. (doi:10.1103/PhysRevA.90.011801)

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Publisher's URL: http://dx.doi.org/10.1103/PhysRevA.90.011801

Abstract

Laser Doppler velocimetry is a technique used to measure linear velocity, ranging from that of exhaust gases to blood flow. A rotational analog of laser Doppler velocimetry was recently demonstrated, using a rotationally symmetric interference pattern to probe the angular velocity of a spinning object. In this work, we demonstrate the use of a diffraction-limited structured illumination pattern to measure the angular velocity of a micron-sized particle trapped and spinning at tens of Hz in an optical trap. The technique requires no detailed knowledge of the shape of the particle, or the distribution of scatterers within it, and is independent of the particle's chirality, transparency, and birefringence. The particle is also subjected to Brownian motion, which complicates the signal by affecting the rotation rate and the rotation axis. By careful consideration of these influences, we show how the measurement is robust to both, representing a technique with which to probe the rotational motion of microscale particles.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Gibson, Dr Graham and Lavery, Dr Martin and Lee, Mr Michael and Padgett, Professor Miles and Speirits, Dr Fiona and Phillips, Dr David and Barnett, Professor Stephen
Authors: Phillips, D. B., Lee, M. P., Speirits, F. C., Barnett, S. M., Simpson, S. H., Lavery, M. P. J., Padgett, M. J., and Gibson, G. M.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Physical Review A: Atomic, Molecular and Optical Physics
Publisher:American Physical Society
ISSN:1050-2947
ISSN (Online):1094-1622
Copyright Holders:Copyright © 2014 American Physical Society
First Published:First published in Physical Review A: Atomic, Molecular and Optical Physics 90(1):011801
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher.

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
542471Optical Atomic Force MicroscopyMiles PadgettEngineering & Physical Sciences Research Council (EPSRC)EP/I007822/1P&A - PHYSICS & ASTRONOMY