Evanescent polarization holographic recording of sub-200-nm gratings in an azobenzene polyester.
I demonstrate high-resolution polarization holographic recording with evanescent waves in a thin film of an azobenzene polyester deposited directly on the hypotenuse of a highly refractive prism. A spatial frequency greater than 7000 lines/mm and diffraction efficiency greater than 1% have been achieved. It was found that diffraction efficiency increases in the dark after the writing beams have been switched off. The biphotonic effect found in other azobenzene polymers, which converts cis states of the azobenzene to trans states followed by an ordering process that is due to aggregation, is proposed as the reason for this increase in diffraction efficiency.
Ramanujam
P S
PS
Optics and Fluid Dynamics Department, Risø National Laboratory, DK-4000 Roskilde, Denmark. ramanujam@risoe.dk