Polarization effects in optical tweezers.

We extend the MDSA (Mie-Debye spherical aberration) theory of trapping forces in optical tweezers, previously developed for circularly polarized trapping beams, to linear polarization. Although it does not significantly affect the trap stiffness, linear polarization may introduce a strong axial asymmetry of the optical forces near the edge of a trapped microsphere, arising from Mie resonance effects. [ABSTRACT FROM AUTHOR]