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All in a Spin: Rotating Trapped Microspheres

Hosted By: Optical Trapping and Manipulation in Molecular and Cellular Biology Technical Group

09 February 2023 17:00 - 18:00

Eastern Time (US & Canada) (UTC -05:00)

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In science fiction, one is familiar with moving objects using laser beams, evoking concepts such as a “tractor beam.” In the laboratory, science fiction turns into science fact: a powerful technique known as “optical tweezers” (OT) shows that micrometer-sized particles (and even biological material and atoms) can be grabbed, moved, and generally manipulated without any physical contact using optical forces. This is a powerful demonstration of the optical dipole or gradient force in action, and this approach was recognized in the Nobel Prize in Physics in 2018.

In the last two decades, we have seen the emergence of the rotation of trapped microspheres. This has, in particular, been driven by the use of birefringent microparticles that can be set into rotation using trapping beams that are circularly polarized. In this webinar hosted by the Optical Trapping and Manipulation in Molecular and Cellular Biology, Kishan Dholakia will describe this area and show how such particles have opened up new vistas in biological studies of viscosity, given insights into the fundamental aspects of the angular momentum of light, and led to the emergence of the field of rotational levitated optomechanics.

What You Will Learn:
• Use of optical tweezers to cause birefringent microparticles to spin about an axis
• The dynamics of rotating microparticles and their coupled motions
• Applications of rotating microparticles in biological viscosity measurements

Who Should Attend:
• Physicists, biologists, and engineers interested in optical trapping, optical forces, light-matter interactions, and levitated optomechanics;
• Physicists, biologists, and engineers interested in applications of optical trapping in micro-rheology are particularly related to the internal viscosity of cells and other biological structures.

About the Presenter: Kishan Dholakia from The University of Adelaide, University of St. Andrews

Kishan Dholakia is a Professor in the School of Biological Sciences at the University of Adelaide, Australia, and in Physics at the University of St Andrews, Scotland. He works on advanced imaging, beam shaping, and optical manipulation leading a group of around 20 researchers. He has published over 350 journal papers. His work is cited in the Guinness book of Records 2015. He is a Fellow of the Royal Society of Edinburgh, Optica, and SPIE. In 2016 he won the R.W. Wood Prize of Optica (formerly OSA). In 2017 he won the IOP Thomas Young Medal and Prize and is the 2018 recipient of the SPIE Dennis Gabor Award. In 2021 he won an Australian Research Council Laureate Fellowship. He was establishing a new Centre of Light for Life in Adelaide, South Australia, that will span work in photonics for trapping, imaging, and precision measurement.


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