Stark effect in dye-doped polymers studied by photochemically accumulated photon echo

We study theoretically and experimentally the influence of a homogeneous static electric field on a photochemically accumulated stimulated photon echo in dye-doped polymers. The dependence of the time profile of the echo signal on the strength of the electric field is evaluated in the case of a linear Stark effect. Experiments using polymers doped with organic dye molecules are carried out at low temperature, and our new technique is applied to determine the difference of the permanent dipole moment in the ground and the first excited singlet electronic state of the impurity molecules.