Nonlinear phenomena in organic multilayers

In the last years there has been a surge of interest in the study of layered systems grown by organic molecular beam deposition. Such a progress has prompted us to consider novel layered structures containing either heterojunctions between a molecular solid and an inorganic semiconductor or donor-acceptor interfaces between crystalline organic materials. Here, we review the striking resonant and non-resonant optical nonlinearities and electro-optical effects associated with the hybrid excitons and the interface charge transfer excitons characteristic of such systems.