Anomalous behavior of a three-dimensional, optically trapped, super-paramagnetic particle

0434983 - ÚPT 2015 RIV US eng C - Conference Paper (international conference)
Šiler, Martin - Jákl, Petr - Brzobohatý, Oto - Ježek, Jan - Zemánek, Pavel
Anomalous behavior of a three-dimensional, optically trapped, super-paramagnetic particle.
Optical Trapping and Optical Micromanipulation XI (Proceedings of SPIE 9164). Bellingham: SPIE, 2014, 916436:1-6. ISBN 9781628411911. ISSN 0277-786X.
[Optical Trapping and Optical Micromanipulation /11./. San Diego (US), 17.08.2014-21.08.2014]
R&D Projects: GA ČR GPP205/12/P868; GA MŠMT(CZ) LO1212; GA MŠMT ED0017/01/01
Institutional support: RVO:68081731
Keywords : Particles * Photodiodes * Diagnostics * Lasers * Optical manipulation * Optical tweezers
Subject RIV: BH - Optics, Masers, Lasers

Super-paramagnetic particles are used extensively in diagnostics and other research applications for the purification of cells, biomolecules and assays. Here, we demonstrate full 3D optical manipulation of such sub-micrometer sized particle using optical tweezers. We report three types of anomalous behavior of such a trapped particle. Firstly, the analysis of particle motion recorded by the quadrant photodiode reveals spikes in the total detected intensity that are formed by a set of very fast oscillations. Secondly, the dependence of trap stiffness on the laser power deviates from the expected linear increase for higher trapping powers. And further, such a particle cannot be optically trapped above certain trapping power threshold. We speculate that these effects are caused by particle internal structure and by its heating.
Permanent Link: http://hdl.handle.net/11104/0238914