This paper uses the integral Rayleigh–Sommerfeld transformation of the first type and an expansion in plane waves to investigate the nonparaxial phenomena that appear when optical elements are combined (using the lensacon as an example) even with a low numerical aperture. The contribution of various components of the vector field when high-aperture optical elements are used in tandem was also taken into account. Based on our studies, it is shown that, in the case of radial polarization, supplementing a lens with an axicon makes it possible to substantially strengthen the contribution of the longitudinal component and to overcome the diffraction limit in the overall intensity by a method that is an alternative to using an annular stop.
© 2011 OSA
Original Manuscript: January 20, 2011
Published: November 30, 2011
S. N. Khonina, N. L. Kazanskiĭ, A. V. Ustinov, and S. G. Volotovskiĭ, "The lensacon: nonparaxial effects," J. Opt. Technol. 78, 724-729 (2011)