High-aspect-ratio microtubes with variable diameter and uniform wall thickness by compressing Bessel hologram phase depth.

In this Letter, we present a light field regulation method to form a ring light field with controllable density distribution. This method is to compress the phase modulation depth of Bessel holograms superimposed with blazed gratings and tune the diffraction efficiency of the superimposed holograms by gray scale. The experimental light field generated by the superimposed holograms is consistent with the simulation results. By designing the phase modulation depth of the superimposed holograms with different parameters, ring light fields with suitable intensity distribution are obtained, and the fabrication of ring microstructure with uniform wall thickness is realized. Finally, as a special case of processing, dynamic holographic processing of high-aspect-ratio microtubes with variable diameter and uniform wall thickness is demonstrated.