Diffraction optical field of the Bessel beam through elliptical annular aperture

Abstract

Based on Fresnel diffraction theory and complex Gaussian function expansion of hard-edged aperture, the optical field formula of Bessel beam propagating through an elliptical annular aperture is derived, and the transverse intensity distribution of the beam is numerically simulated. The changes of the optical field and the propagation process of the diffracted beam behind the elliptical annular aperture are studied. In the experiment for the first time, a quasi non-diffracting beam is generated by an axicon and the patterns that are due to the beam diffraction by an elliptical annular aperture at different propagation distances are observed with a charge-coupled device camera. The theoretical analysis and experimental results both show that Bessel beam passing through an elliptical annular aperture can generate a hollow beam.

A deformable annular slit for generating elliptical Bessel beams

“…An alternative method combined an axicon and an elliptical slit but was only able to generate hollow Bessel beams. 22) Metasurfaces have been utilized in forming elliptical versions of wavelength-independent subwavelength Bessel beams, 23) but preparing effective surfaces of this type requires complex nanofabrication procedures. With the deformable annular slit discussed in this present work, we provide a low-cost method of generating elliptical zero-order Bessel beams.…”