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Two diffusion photopolymer for sharp diffractive optical elements recording

2015; Optica Publishing Group; Volume: 40; Issue: 14 Linguagem: Inglês

10.1364/ol.40.003221

1539-4794

Sergi Gallego, Roberto Fernández, Andrés Márquez, Manuel Ortuño, Cristian Neipp, Michael R. Gleeson, John T. Sheridan, Augusto Beléndez,

Photonic and Optical Devices

Photopolymers as recording media are widely used in optical applications. In such materials, changes in the phase of the transmittance function are generated during exposure due to refractive index and thickness modulations. These changes arise primarily as a consequence of photopolymerization and mass transport processes. Characterizing polymers' performance, for example, quantifying the value of monomer diffusion, is therefore very important. Applying index matching, the volume and surface optical effect are separated in an acrylamide/polyvinylalcohol (AA/PVA) material. Using a simplified model that includes the effects of the holes produced during polymerization, both hole and monomer diffusion are analyzed. The analysis presented indicates higher material sensitivity than previously estimated. The results also indicate the possibility of recording sharper diffractive optical elements profiles, like blazed gratings, having diffraction efficiencies higher than 80%.