A sophisticated modeling program was used recently to predict the trapping
and the manipulation properties of elongated cylindrical objects in the foc
al region of a high-intensity laser beam. On the basis of the model, the cy
linders should align their longest diagonal dimension with the propagation
axis of the laser beam and follow the beam when it is displaced transverse
to the cylinder's central axis. Experimental confirmation of the cylinder's
behavior is presented and confirms the suitability of the enhanced ray-opt
ics approach to modeling micrometer-scale objects in optical-trap environme
nts. (C) 1999 Optical Society of America.