Optomechanical manipulation of nanoparticles with a magnetic response in a Gaussian beam

Nanoparticles made from dielectric materials with a high refractive index have caused a surge of interest and have been proposed for various all-dielectric nanophotonic applications. In this regard, the development of optical manipulation technology for such nanoparticles becomes an important task. High-index nanoparticles support electric and magnetic multipole responses in the visible wavelength range, and interference between such modes can manifest itself in optical forces. Here, we present a study of the optical forces acting on silicon nanoparticles in a Gaussian beam, calculated analytically using the Mie theory, as well as the numerical simulations results based on the Maxwell stress tensor. We have shown that the interaction of а laser beam electromagnetic field with electric and magnetic dipoles in a nanoparticle can lead to a possible anti-trapping effect. This behavior of the particle is not typical for optical tweezers, where the particle is usually attracted to the beam axis.