Sharp focusing of linearly polarized asymmetric Bessel beam

We conduct the numerical and experimental study of sharp focusing of a linearly polarized asymmetric Bessel beam with topological charge n = 3 and a crescent-shaped transverse intensity pattern. Using the Debye integral, we show that in the focal plane of a high NA aplanatic lens (NA = 0.9 – 0.95) the intensity distribution is also crescent-shaped. Using the FDTD method it is shown that a binary zone plate with NA = 0.995 also forms a crescent-shaped focal spot that is rotated around the optical axis. An asymmetric Bessel beam was generated using a spatial light modulator (SLM) and focused using an immersion objective with NA = 1.25. A crescent-shaped intensity pattern formed in the focal plane was rotated by 90 degrees relative to the SLM-aided crescent.