Real-time control of optical tweezers

Anders E. Wallin, Heikki Ojala, Anders Korsbäck, Edward Haeggström, Roman Tuma

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific


Optically trapped microshperes can be manipulated by steering the trap beam, while the object position is measured with sub-nanometer resolution. A fast steering system is required to create feedback loop for measurements at a constant force or to increase position detection precision by trap stiffening. Using a real-time re-programmable digital signal processor, we combine steering and position detection to create a fast and versatile closed-loop feedback controlled instrument. We describe the construction and calibration of the instrument. We show that a proportional gain position-clamp algorithm can achieve about 10-fold increase in effective trap stiffness while higher gains lead to unwanted resonances.
Original languageEnglish
Title of host publicationOptical Trapping and Optical Micromanipulation IV
PublisherInternational Society for Optics and Photonics SPIE
Publication statusPublished - Sept 2007
MoE publication typeB3 Non-refereed article in conference proceedings

Publication series

SeriesProceedings of SPIE


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