Rodrigo, Peter JohnDaria, Vincent RicardoGlückstad, Jesper2015-11-112015-11-110003-6951http://hdl.handle.net/1885/16459We transform a TEM00 laser mode into multiple counterpropagating optical traps to achieve four-dimensional simultaneous manipulation of multiple particles. Efficient synthesis and dynamic control of the counterpropagating-beam traps is carried out via the generalized phase contrast method, and a spatial polarization-encoding scheme. Our experiments genuinely demonstrate real-time, interactive particle-position control for forming arbitrary volumetric constellations and complex three-dimensional trajectories of multiple particles. This opens up doors for cross-disciplinary cutting-edge research in various fields.This work has been funded by the European Science Foundation through the Eurocores-SONS program and partially by an internal grant awarded by Risø National Laboratory.http://www.sherpa.ac.uk/romeo/issn/0003-6951..."Publishers version/PDF may be used on author's personal website, institutional website or institutional repository" from SHERPA/RoMEO site (as at 11/11/15). Copyright 2005 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters and may be found at https://doi.org/10.1063/1.1866646Keywords: Diffractive optics; Laser modes; Light modulation; Light polarization; Light propagation; Synthesis (chemical); Transmission electron microscopy; Generalized phase contrast (GPC); Optical manipulation; Optical traps; Colloids2005-02-1110.1063/1.18666462015-12-09