3D transformations of light fields in the focal region implemented by diffractive axicons

Three-dimensional transformations of light fields were investigated, including such characteristics as intensity distribution and polarisation state, in the focal region at tight focusing and in the paraxial regime due to the lens apodisation by a diffraction axicon with different structures (linear, binary, spiral axicons). Theoretical analysis demonstrates the different possibilities of such transformations and significant differences in results depending on the focusing modes (sharp or paraxial). The experimental results obtained were in good agreement with the simulation results, demonstrating that optical systems employing lens-axicon combinations may be useful in the laser trapping of nano- and microparticles, optical microscopy, and improvement of high-capacity information storage techniques.