Modeling highly focused laser beam in optical tweezers with the vector Gaussian beam in the T-matrix method

The vector Gaussian beam with high-order corrections is used to describe accurately the laser beam up to numerical aperture NA = 1.20 in the optical tweezers for trapping nanoparticles. The beam is then expanded in the T-matrix method into the vector spherical wave function (VSWF) series using the point matching method with a new selection of the matching points. The errors in the beam description and in the VSWF expansion are much lower than those that occur in the paraxial Gaussian beam model. (c) 2012 Optical Society of America