Energy Backflow in Tightly Focused Optical Vortex

摘要

We numerically investigated the focusing of optical vortices with topological charge of 2, wavelength of 532 nm and circular polarization by a diffractive lens with a numerical aperture NA = 0.95. The simulation was carried out using the Richards-Wolf formulae and FDTD-method. It was shown that the focusing of optical vortices with circular polarization by a wide-aperture diffractive lens can produce intensity distribution with a negative component of the longitudinal component of the Poynting vector.