title: Photoinduced grating formation in a polymer containing azo-carbazole dyes.
abstract: Although some azo-carbazole derivatives attached on or doped into inert polymers are known to show photorefractive effect without external electric field, the origin of their asymmetric energy transfer in two-beam coupling experiments were unknown. We made the two-beam coupling experiment followed by sample translation and one-beam diffraction at 633 nm for thick films composed of 3-[(4-nitrophenyl)]azo-9H-carbazole-9-ethanol (NACzEtOH) and poly(methylmethacrylate), finding that photoinduced gratings grew in several minutes accompanied with phase displacement of the gratings, but the phase shift was not always synchronized with the refractive index modulation. We reformulated the Kogelnik's coupled-wave theory with strict energy conservation law for analysis. Comparison of the grating growth and erasure at 532 nm to Disperse Red 1 (DR1), the most well-known azo dye showed that the photoisomerization was dominant at this wavelength and that the azo-carbazole dyes were faster in response time and more resistive to erasure than DR1.
authors.affiliation: Chitose Insitute of Science and Technology, Bibi Chitose Hokkaido, Japan. y‐kawabe@photon.chitose.ac.jp
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kawabe
authors.forename: Kodai
authors.initials: K
authors.lastname: Fukuzawa
authors.forename: Takuya
authors.initials: T
authors.lastname: Uemura
authors.forename: Katsufumi
authors.initials: K
authors.lastname: Matsuura
authors.forename: Toshio
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Nishide
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sasabe