Dresden 2014 – wissenschaftliches Programm

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KR: Fachgruppe Kristallographie

KR 10: Crystallography in Nanoscience (KR jointly with MI)

KR 10.3: Vortrag

Donnerstag, 3. April 2014, 11:30–11:45, CHE 184

Mapping the velocity field around a micro-oscillator in water — •Spas Nedev¹, Sol Carretero-Palacios¹, Silke R. Kirchner¹, Frank Jäckel^1,2, and Jochen Feldmann¹ — ¹Photonics and Optoelectronics Group, Physics Department and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Amalienstr. 54, 80799 Munich, Germany — ²Department of Physics and Stephenson Institute for Renewable Energy, University of Liverpool, Chadwick Building, Peach Street, Liverpool, L69 7ZF, United Kingdom

Optical trapping in combination with microfluidics provides novel analytical and sensing capabilities. Here we show an experimental and theoretical approach to detect and map the velocity field around a micro-oscillator in water. Fluidic vibrations created by a micro-source, an optically trapped silica particle set to oscillate in a dipole-type mode, lead to displacement of another twin silica particle independently trapped in its vicinity acting as a detector. Fourier analysis of the motion of the detecting particle at different points in space and time provides the velocity map around the oscillating microsphere. The combination of measured velocity field and microfluidic theoretical models reveals that the measured fields are dominated by microfluidic contributions, with a significant acoustic contribution. The concept introduced here allows for the study of the fluidic and acoustic near fields close to micro-source in water. Furthermore it serves a basis for nano-positioning system for location and recognition of moving sources that may be applied to artificial micro-objects and living organisms.