3D characterization of the forces in optical traps based on counter-propagation beams shaped by a spatial light modulator

M. V. Kristensen, T. Lindballe, A. Kylling, Darwin Palima, Jesper Glückstad, S.R. Keiding, H. Stapelfeldt

Research output: Contribution to journalConference articleResearchpeer-review

Abstract

An experimental characterization of the 3D forces, acting on a trapped polystyrene bead in a counter-propagating beam geometry, is reported. Using a single optical trap with a large working distance (in the BioPhotonics Workstation), we simultaneously measure the transverse and longitudinal trapping force constants. Two different methods were used: The Drag force method and the Equipartition method. We show that the counterpropagating beams traps are simple harmonic for small displacements. The force constants reveal a transverse asymmetry as - = 9.7 pN/µm and + = 11.3 pN/µm (at a total laser power of 2x35 mW) for displacements in opposite directions. The Equipartition method is limited by mechanical noise and is shown to be applicable only when the total laser power in a single 10 µm counter-propagating trap is below 2x20 mW.
Original languageEnglish
JournalProceedings of SPIE, the International Society for Optical Engineering
Volume7762
Pages (from-to)12
ISSN0277-786X
DOIs
Publication statusPublished - 2010
EventSPIE NanoScience + Engineering 2010, The International Society for Optical Engineering (SPIE), 2010 - San Diego, California, USA
Duration: 1 Jan 2010 → …

Conference

ConferenceSPIE NanoScience + Engineering 2010, The International Society for Optical Engineering (SPIE), 2010
CitySan Diego, California, USA
Period01/01/2010 → …

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