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Updated: May 27, 2026
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A Protocol for Real-time 3D Single Particle Tracking
Published on: January 3, 2018
Fast parallel interferometric 3D tracking of numerous optically trapped particles and their hydrodynamic interaction
Dominic Ruh1, Benjamin Tränkle, Alexander Rohrbach
1Laboratory for Bio- and Nano- Photonics, Department of Microsystems Engineering-IMTEK, University of Freiburg, Georges Köhler Allee 102, 79110 Freiburg, Germany.
Optics Express
|November 24, 2011
Summary
We developed a faster, more precise method for tracking micron-sized beads in 3D using optical trapping and interferometry. This technique enhances the study of dynamic processes in soft matter systems.
Area of Science:
- Soft Matter Physics
- Biophysics
- Materials Science
Background:
- Multi-dimensional particle tracking is crucial for understanding dynamic processes in soft matter.
- Existing techniques face limitations in speed and precision for tracking numerous particles.
Purpose of the Study:
- To present a novel, high-speed, and high-precision method for parallel, three-dimensional tracking of micron-sized beads.
- To enable advanced investigations into the dynamics of soft matter systems.
Main Methods:
- Utilized an acousto-optic deflector and quadrant-photodiodes for optical trapping.
- Employed back-focal plane interferometry for nanometer-precision tracking at kHz frequencies.
- Implemented time-multiplexing of laser focus for rapid 3D calibration of multiple traps.
Main Results:
- Achieved tracking of numerous optically trapped beads at tens of kHz with nanometer precision.
- Demonstrated individual calibration of traps and tracking signals in seconds.
- Presented 3D histograms and calibration constants for nine beads in a quadratic arrangement.
Conclusions:
- The developed method significantly surpasses existing techniques in speed and precision for 3D particle tracking.
- The technique is applicable to more beads and arbitrary 2D arrangements.
- Successfully applied the method to investigate hydrodynamic coupling and diffusion anomalies in trapped spheres.
