Electroabsorption spectroscopy of beta-carotene and alpha omega-bis(1,1-dimethylheptyl)-1,3,5,7,9,11,13,15-hexadecaoctaene

We investigate the electric-field-induced change in the absorbance (i.e. electroabsorption response) of samples of beta-carotene and alpha,omega-bis(1,1-dimethylheptyl)-1,3,5,7,9,11,13,15-hexadecaoctaene dispersed in a polystyrene matrix. From the change in absorbance, the refractive index and the thickness of the polymer film, the third-order nonlinear d.c. Kerr susceptibility, chi((3)) (-omega,0,0,omega), can be calculated via the Kramers-Kronig relationship. Results are also presented for the simulated electroabsorption of beta-carotene, derived from calculation of the absorption both in the presence and absence of an applied electric field.