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Tuesday, October 12, 2010

Real-time particle tracking at 10,000 fps using optical fiber illumination

Oliver Otto, Fabian Czerwinski, Joanne L. Gornall, Gunter Stober, Lene B. Oddershede, Ralf Seidel, and Ulrich F. Keyser

We introduce optical fiber illumination for real-time tracking of optically trapped micrometer-sized particles with microsecond time resolution. Our light source is a high-radiance mercury arc lamp and a 600μm optical fiber for short-distance illumination of the sample cell. Particle tracking is carried out with a software implemented cross-correlation algorithm following image acquisition from a CMOS camera. Our image data reveals that fiber illumination results in a signal-to-noise ratio usually one order of magnitude higher compared to standard Köhler illumination. We demonstrate position determination of a single optically trapped colloid with up to 10,000 frames per second over hours. We calibrate our optical tweezers and compare the results with quadrant photo diode measurements. Finally, we determine the positional accuracy of our setup to 2 nm by calculating the Allan variance. Our results show that neither illumination nor software algorithms limit the speed of real-time particle tracking with CMOS technology.

DOI

3 comments:

Unknown said...

I notice in the article, they mention 'supplementary material' but it's not at the end of the article, nor can I find it on the Optics InfoBase citation page (DOI). Any idea where this material might be located?

Antonio Neves said...

I believe the 'supplementary material' became Ref. 23. The preprint for it can be found at: http://arxiv.org/abs/1008.1413

Unknown said...

Thank you so much!

I ended up e-mail Fabian Czerwinski and he gave me a screenshot of the LabVIEW program but this is much mroe comprehensive.

Thank you!