Energy flow of strongly focused cylindrical vector beams on higher-order Poincaré sphere

Energy flow is an important dynamic characteristic of light field that has recently gained tremendous interest due to its useful applications in light–matter​ interactions. Using the Richards–Wolf vectorial method, a model for calculating the transverse and longitudinal components of the electric and magnetic fields as well as the Poynting vector of tightly focused vector beams on a higher-order Poincaré sphere is presented. The evolution of the energy flow in the tightly focused field is explored from the perspective of the Poincaré sphere. In addition, its relation to the optical degrees of freedom of the input field is revealed based on the model. Calculations reveal that ellipticity and handedness affect the magnitude and direction of the transverse energy flow, respectively, and have almost no effect on the longitudinal energy flow, while the orientation has no effect on both transverse and longitudinal energy flows. These findings may be helpful in applications that enable transport of particles.