Optical limiting of multilayer sol-gel structures containing fullerenes

Pyrrolidino-fulleren molecules with functional groups for improving their solubility in polar solvents and for their linking to a sol-gel matrix have been included in an ORMOSIL matrix based on a glymo silicon alkoxide. Optical limiting properties of the solutions of the fullerene derivatives have been fitted with a six level model and it has been shown that their behaviour is retained when the molecules are included in the sol-gel matrix. Multylayer structures based on the bottleneck principle have been obtained and their optical limiting properties measured. The multilayer architecture improves the optical limiting properties of the materials but a better control of the performance will be achieved when the non-linear beam propagation properties in the medium will be considered.