LARGE 3RD-ORDER OPTICAL NONLINEARITIES IN ORGANIC POLYMER SUPERLATTICES

Large second hyperpolarizabilities, 〈γxxxx〉, have been measured in solutions of two recently prepared organic polymer superlattices. These compounds have period aromatic and quinoidal structures and differ from each other by a side group substituent. The values observed are 1.6×10-29 esu for the parent copolymer and 3.7×10 -30 esu for its acetoxy derivative. The corresponding values of χ(3)xxxx for the solid phase are estimated to be 2.7×10 -7 and 4.5×10-8 esu. Time-resolved degenerate four-wave mixing measurements, made at 532 nm, showed that the dynamics of the parent copolymer were faster than the 25 ps resolution of the instrument while the derivative exhibited an additional slower response component.