Advanced photopolymerizable material for particular diffractive optical elements

A photopolymerizable system sensitive in the 450-550 nm range is proposed in which thick phase holograms are recorded in situ through polymerization and diffusion processes. Three applications are presented. i) Multiplexed holograms were created with a view to optical edge extraction filtering. Several slanted fringe transmission gratings were recorded in the same location with less than 0.5° changes of the slant angle and 0.1 ?m of the fringe spacing. Diffraction angles were not affected by shrinkage of the polymer layer that occurred during the successive exposures. By optimization of the recording schedule, it was possible to obtain the same fair diffraction efficiency for each grating at the expected angle, reading them simultaneously at normal incidence. ii) Taking advantage of the two glass plates laminating the emulsion, transmission and reflection gratings with fringe spacings lower than the incident wavelength were recorded with a view to fabrication of substrate-mode diffractive elements. iii) Binary amplitude elements with pixel size of 20 ?m were duplicated by imaging in the polymerizable system, giving rise to thick phase holograms. The diffraction efficiency and the quality of the reconstructed image were studied as a function of the recording conditions.