An article written by Baluktsian et Al, investigates the quality of vortex beams in the visible spectrum which are used for a wide range of applications. They studied “the mode conversion efficiency (MCE), vortex structure and stability (in terms of vortex splitting) of the vortex fields generated by spiral zone plates (SZP)”. The findings “link the parameters of optics to the properties of the vortices and help to maximize the performance of ZP based vortex generators for future applications”
For the fabrication process the ZPs were patterned onto Silson’s gold coated silicon nitride membranes (1µm thick), with the purpose of the gold layer being “to avoid ion beam shifts caused by membrane charging”. The fabrication process was performed using direct-write ion beam lithography.
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