Optical vortex generation by nanostructured vortex phase plates integrated with single-mode fibers

We have developed a new optical vortex generator based on flat-surface nanostructured gradient index vortex phase plate (VPP) integrated with optical single mode fiber (SMF). The considered phase plate was constructed of set of designed discrete sub-wavelength rods made of two thermally matched glasses with high and low refractive indices. We used modified stack and draw technique to fabricate the nanostructured VPPs which exhibit the effective refractive index distribution changing azimuthally due to the effective medium theory. The optical performance of the fabricated systems was experimentally investigated. The obtained results showed good agreement with the theoretical prediction of vortex generations.