Axial and lateral trapping efficiency of Laguerre-Gaussian modes in inverted optical tweezers

Within inverted optical tweezers we measure both the lateral and axial trapping efficiency obtained with Gaussian and high-order Laguerre-Gaussian beams. Our results confirm that, for larger particles, the axial trapping is improved by using a Laguerre-Gaussian beam but, contrary to earlier suggestions, that the lateral efficiency is unchanged. We show that this latter observation is compatible with a ray-optical model of the trapping mechanism