| abstract |
The invention relates to an optically non-linear active waveguiding material comprising an optically transparent polymer and a non-linear optical dopant comprising more than one donor-π-acceptor unit. n Dopants comprising more than one donor-π-acceptor unit, especially dopants in which the donor-π-acceptor units are positioned in a cyclic group, have a high hyperpolarisability and a charge-transfer absorption band wavelength which is about the same as that of dopants with only one donor-π-acceptor unit. n Especially suitable dopants for use are calix(4)arenes. These are provided with acceptor groups at the upper rim and with donor groups at the lower rim. In addition to having excellent hyperpolarisability, these compounds were found to be readily soluble in host polymers, such as PMMA and polystyrene. Because of their charge-transfer absorption band at a low wavelength, optically non-linear active waveguiding structures containing such dopants are suitable for use as frequency doublers. n The invention further relates to hitherto undisclosed calix(4)arenes functionalised with nitrostilbene groups, cyanostilbene groups, sulphonyl stilbene groups, sulphonate stilbene groups, azobenzenes or benzylidene aniline compounds. |