Strong dark self-enhancement, the increase in diffraction efficiency after irradiation, has been reported previously for dichromated-gelatin gratings. Here a more-detailed study of this self-enhancement effect is presented. The self-enhancement in dichromated-gelatin gratings was of the order of 10–100, depending on the pH and on the dichromate concentration of the solution used for the preparation of dichromated-gelatin films. The highest self-enhancement gain occurred when pH was high and dichromate concentration was low. The increase in the diffraction efficiencies of the gratings continued over 3 months.
© 1999 Optical Society of America
Original Manuscript: March 25, 1999
Revised Manuscript: July 26, 1999
Published: December 10, 1999
Roma Grzymala and Tuula Keinonen, "Dark self-enhancement in dichromated-gelatin gratings: a detailed study," Appl. Opt. 38, 7222-7227 (1999)