ABSTRACT
What is believed to be the first evidence of an all-optical orientation of a highly transparent polymer is presented. The samples are bulk rods of poly(methyl methacrylate) grafted with paranitroaniline (PNA) obtained by use of copolymerization of methyl methacrylate (MMA) monomers mixed with grafted MMA-PNA monomers. Bulk samples were obtained after molding and polishing of the copolymer with standard techniques. Experiments show that the photoinduced second-order(1) susceptibility chi((2)) may occur through molecular reorientation following selective polar excitation of the nonlinear chromophores by simultaneous two- and three-photon absorption on the same electronic level.
ABSTRACT
The permanent all-optical poling of an azo-aromatic acrylic copolymer is experimentally demonstrated by seeding preparation in a backward phase-conjugation geometry. The microscopic mechanism involves an orientational hole burning followed by orientational redistribution caused by trans-to-cis isomerization of the azo-dye chromophores. The characteristic kinetics of monitored by second-harmonic generation.
