Improvement of direct fringe printer for computer-generated holograms

H. Yoshikawa
Nihon University, Japan
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It is becoming possible to calculate computer-generated holograms of three-dimensional objects that have more than one billion pixels, even with normal personal computers. On the other hand, it is not so easy to output the calculated result as a hologram that must have micron order resolution for practical three-dimensional display. We have been developing a fringe printer, which consists of a laser, an X–Y stage and a liquid crystal panel as a spatial light modulator. A fractional part of the entire holographic fringe is displayed on the liquid crystal panel, and the demagnified image of it is recorded on a holographic plate. Then the plate is translated by the X–Y stage to write the next part of the fringe. In this report, a 0.5 M pixel transmission LC panel is replaced by a 1.3 M pixel reflection type panel. Since the number of exposures is reduced, a more than fourfold improvement in the printing speed is obtained. We were able to print a 3 Giga-pixel hologram with 0.87 µm pitch in 137 min.