We investigate the cooperative effects on optical forces in a system of N two
level atoms occupying a volume of dimensions to within λ3, where
lambda is radiation wavelength and is driven by a coherent radiation field with
a spatial profile like Laguerre-Gaussian beam or ideal Bessel beam.We show a
dramatic enhancement on optical forces as well as the angular momentum imparted
to the atom by a factor of N2.Comment: 10 pages + 1 figure (submitted to PRL