Kai Skodzek
Phone:  +44 (0)131 451 4748
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Address William Perkin Annex 1.0
Heriot-Watt University
Edinburgh
EH14 4AS
United Kingdom

 

Project title: Higher order mode manipulation for isotropic 3D cell tomography

Project outline:
Cell biology utilises the power of optical microscopy extensively to understand the structures and processes within individual cells, yet most methods are limited in having a lower axial resolution compared to the highly resolved imaging plane. To study sub-cellular structures, detailed information is required in all three dimensions, and so isotropic resolution is desired. One way to obtain isotropic resolution in 3D is by rotating the sample through the high-resolution imaging plane, and reconstructing the data to give the 3D structure.

Dual beam laser traps offer the capability of holding and rotating individual living cells in a non-invasive and non-contact way. Traditional dual-beam traps use two rotationally symmetric Gaussian beams to form a trap, however this results in the trapped cell being free to rotate under thermal motion. By modifying one beam to become a non-rotationally symmetric higher-order linearly polarized LP01 mode, it is possible to align single cells or multicellular clusters effectively. Higher order modes propagating in a laser fibre are the product of polarisation dependent mode mixing. We show that a series of piezo-electric blocks positioned variously orientated on the outside of the fibre are capable of manipulating the modes travelling within, making it possible to control the orientation of the LP01 mode without any free-space components. Integrating this into a dual-beam trap allows the rotation of cells perpendicular to the imaging axis. Rotating cells tomographically in a dual beam trap and holding them stationary while imaging enables a user friendly lab on a chip device for isotropic 3D cell tomography first on confocal microscope systems and possibly on a SIM microscope system.

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Conferences:

Photonex Scotland 2015, 2016
ESRIC Summer School 2016