Sj. Strutz et Lm. Hayden, Quasipermanent photochemical gratings in a dual use photorefractive polymer composite, APPL PHYS L, 74(19), 1999, pp. 2749-2751
The dual nature of (3-(2-(4-(N,N-diethylamino)phenyl)ethenyl)-5,5-dimethyl-
1,2-cyclohexenylidene)propanedinitrile (Lemke-e) allows us to write both qu
asipermanent and erasable holographic gratings in the same storage volume.
In the presence of a triplet excited sensitizer, Lemke-e undergoes a photoc
hemical reaction allowing the creation of quasipermanent photochemical holo
graphic gratings. In addition, applying an electric field to the composite
allows the storage of erasable photorefractive holograms in the same locati
on as previously stored permanent photochemical holograms. Photochemical gr
atings (eta > 10%) can be written in less than 1 min while photorefractive
gratings (eta > 50%) can be written in less than 1 s. The photochemical gra
tings have a dark lifetime of several days. (C) 1999 American Institute of
Physics. [S0003-6951(99)00619-1].