Reply to comment on "Trapping forces, force constants and potential depths for dielectric spheres in the presence of spherical aberrations"

We acknowledge the helpful comment by Chaumet [Appl. Opt. 43, 1825 (2004)] on a recent study [Appl. Opt. 41, 2494 (2002)] in which we used a mathematical expression for the optical scattering and gradient forces, which had been introduced in an earlier paper [J. Opt. Soc. Am. A 18, 839 (2001)]. Our reply to the comment gives us the chance to clarify interesting points and to present a novel, to our knowledge, derivation of the two force components from the basic electromagnetic force density on a small polarizable particle. Our final expression [Appl. Opt. 41, 2494 (2002)] for the optical trapping force on particles in the Rayleigh–Gans regime (diameter less or equal to wavelength) in a diffraction-limited, vectorial focus remains correctly published.