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In light optics the use of holographic beam shaping has been largely used to obtain complicated wavefronts [1] and vortex beams but recently holograms have been used in the electron vortex beam generation [2]. We show here our recent improvement in the technology of hologram fabrication by means of “phase hologram”[3] replacing the amplitude hologram so far used. Phase hologram appropriately changes the phase of the wavefront by a modulation of thickness in a Silicon nitride thin membrane.By means of phase hologram we could produce different beam shape in both Fresnel and Fraunhofer regime. Moreover we engineered the hologram shape to obtain high efficiency on the generated wavefunction. Presently we could demonstrate an efficiency of 40% in the generation efficiency for a single beam. This is the best performance ever shown and is much higher than amplitude hologram so far used.
Cambridge University Press
Publication date: 
1 Aug 2014

Vincenzo Grillo, Ebrahim Karimi, Roberto Balboni, Gian Carlo Gazzadi, Stefano Frabboni, Erfan Mafakheri, Robert W Boyd

Biblio References: 
Volume: 20 Issue: S3 Pages: 228-229
Microscopy and Microanalysis