... Beam propagation modeling of modified volume Fresnel zone plates fabricated by femtosecond laser direct writing Pornsak Srisungsitthisunti,1Okan K. Ersoy,2,*and Xianfan ... 19, 2008 (Doc. ID 101731); published December 24, 2008Light diffraction by volume Fresnel zone plates (VFZPs) is simulated by the Hankel transform beam propaga-tion method (Hankel BPM). The method ... FZP can only be fabri-cated with small diffraction efficiency. The VFZP can be fabricated by femtosecond laser direct writing. This con-cept was experimentally demonstrated with an eight-layer...