Optical Force and Torque on a Graphene-Coated Gold Nanosphere by a Vector Bessel Beam

In the framework of the generalized Lorenz–Mie theory (GLMT), the optical force and torque on a graphene-coated gold nanosphere by a vector Bessel beam are investigated. The core of the particle is gold, whose dielectric function is given by the Drude–Sommerfeld model, and the coating is multilayer graphene with layer number N, whose dielectric function is described by the Lorentz–Drude model. The axial optical force [Formula: see text] and torque [Formula: see text] are numerically analyzed, and the effects of the layer number N, wavelength [Formula: see text] , and beam parameters (half-cone angle [Formula: see text] , polarization, and order l) are mainly discussed. Numerical results show that the optical force and torque peaks can be adjusted by increasing the thickness of the graphene coating, and can not be adjusted by changing [Formula: see text] and l. However, [Formula: see text] and l can change the magnitude of the optical force and torque. The numerical results have potential applications involving the trapped graphene-coated gold nanosphere.