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Updated: Jun 24, 2026

Direct Force Measurements of Subcellular Mechanics in Confinement using Optical Tweezers
Published on: August 31, 2021
Three-dimensional force measurements in optical tweezers formed with high-NA micromirrors
Fabrice Merenda1, Mathieu Grossenbacher, Sylvia Jeney
1Advanced Photonics Laboratory, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland. fabrice.merenda@a3.epfl.ch
Abstract:
The three-dimensional trap stiffness of optical tweezers formed with high-NA micromirrors is investigated by back-focal-plane interferometry and power spectrum analysis. Normalized stiffness values of kappaxy/Ptrap=1.2(microN/m)/mW and kappaz/Ptrap=0.52(microN/m)/mW in the transverse and axial directions, respectively, have been measured for polystyrene spheres with a radius of 1.03 microm. Compared with high-NA microscope objectives, micromirrors achieve much better trapping performances, particularly in the axial direction.
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