Theoretical prediction of photophoretic force on a dielectric sphere illuminated by a circularly symmetric high-order Bessel beam: on-axis case

Compared to the experimental progresses made in the optical trapping of aerosol particles in gaseous media by means of photophoretic forces, the theoretical analysis of photophoretic forces is less developed, the underlying mechanisms being yet not fully understood. In this paper, theoretical derivations of photopheresis of a dielectric sphere in gaseous media illuminated by a circularly symmetric Bessel beam of arbitrary order is presented within the framework of generalized Lorenz-Mie theory. An analytic and closed-form formula for the asymmetry factor, which ultimately determines the sense of direction of photophoretic force, is provided. The influences of particle size, absorptivity of the particle, half-cone angle, beam order of the Bessel beam on the asymmetry factor are explored in detail. The method proposed in this paper can be applied to a wider class of axisymmetric beams carrying nonzero topological charges. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

This paper presents theoretical derivations of photopheresis of a dielectric sphere in gaseous media illuminated by a circularly symmetric Bessel beam of arbitrary order within the framework of generalized Lorenz-Mie theory. An analytic and closed-form formula for the asymmetry factor, which determines the direction of photophoretic force, is provided. The influences of particle size, absorptivity of the particle, half-cone angle, and beam order of the Bessel beam on the asymmetry factor are explored in detail.