K. Yang et al., DISPERSIONS OF ELECTROABSORPTION SUSCEPTIBILITIES - APPLICATION TO A POLYMERIC LANGMUIR-BLODGETT-FILM, Optics communications, 144(4-6), 1997, pp. 259-264
The relation between the dispersions of nonlinear optical susceptibili
ties chi((n))(omega;omega,0,...,0) and chi((n-1))(omega;omega,0,...,0)
(for electro-optic process) of organic polymeric materials is studied
based on the premises that the microscopic polarizabilities alpha, be
ta, gamma, delta, ... are derivatives of their next lower order polari
zabilities, with respect to the effective internal field F across the
polarizable pi-conjugated systems, and that these derivative relations
hips are still valid when dynamic (frequency-dependent) processes are
considered. Electroabsorption spectroscopy has been used to determine
the dispersion of chi(113)((2)) and chi(1133)((3)) of a polyamic acid
salt Langmuir-Blodgett film containing covalently bonded azobenzene NL
O chromophores. The results are consistent with our prediction, and co
nfirm the validity of the derivative relationships proposed by Marder
et al. [Science 265 (1994) 632; J. Am. Chem. Soc. 116 (1994) 10703]. T
his LB film also gives appreciable values of both chi(113)((2)) (26 pm
/v) and chi(1133)((3)) (2 X 10(-11) esu). (C) 1997 Elsevier Science B.
V.