Preparation and optical li miting of a novel soluble phenylacetylene copolymer bearing nonlinear chromophoric pendants

A novel soluble conjugated phenylacetylene copolymer containing nonlinear chromophore,poly {[4-ethynyl-4’-(N,N-diethylamino)azobenzene]-co-phenylacetylen} was prepared and its optical li miting(OL) properties were investigated in threedifferent concentration solution with 8ns pluses at 532nm wavelength.The excited state absorption cross-sectionσexof this poly-mer was measured with the Z-scan technique.The optical li miting mechanism was discussed based on nonlinear absorption theo-ry.The results showthat this polymer possesses the larger excited state absorption cross-section than the ground state,indica-ting that the OL performance of this polymer mainly arises fromthe reverse saturable absorption(RSA).