3RD-ORDER NONLINEAR-OPTICAL SUSCEPTIBILITIES BY LASER SELF-TRAPPING AND DEGENERATE 4-WAVE-MIXING IN OLIGOTHIENYLDICYANOVINYLENE SOLUTIONS

The solution third-order non-linear optical susceptibility chi(3) valu es, measured by laser self-trapping at 514.5 nm for chloroform solutio ns of bis(dicyanovinyl)thiophene 4 (2.9 x 10(-7) esu), bis- (dicyanovi nyl)dithienyl 5 (1.1 x 10(-4) esu), bis(dicyanovinyl)trithienyl 6 (1.1 x 10(-5) esu), values are affected by resonance and solution heating effects. Chi(3) (-omega; omega, omega, -omega) was measured by degener ate four-wave mixing at 1064 nm for chloroform (C) and pyridine (P) so lutions of dicyanovinylthiophene 1, dicyanovinyldithienyl 2, dicyanovi nylterthienyl 3, and bis(dicyanovinyl)thiophene 4. The molecular secon d-order hyperpolarizabilities are gamma/esu = 8.7 x 10(-33) (1, C), -6 .3 X 10(-33) (1, P), 2.2 x 10(-33) (2, C), 3.7 x 10(-31) (3,C), 6.1 X 10(-32) esu (3, P), 2.8 x 10(-31) (4, P).