Electroabsorption spectroscopy of β-carotene and α,ω-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 β-carotene and α,ω-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, χ(3)(-ω; 0,0,ω), can be calculated via the Kramers-Kronig relationship. Results are also presented for the simulated electroabsorption of β-carotene, derived from calculation of the absorption both in the presence and absence of an applied electric field.