Recent development in the design of organic materials for optical power limiting

During the past five years there has been considerable progress in the desi gn of organic materials for optical power limiting. Among the more promisin g of the new material approaches are new reverse saturable absorbers (RSA) which derive their limiting capability on the photogeneration of highly abs orbing charge states. Equally intriguing are the new approaches to designin g chromophores with large two-photon cross-sections which give access to hi ghly absorbing transient excited states. It now seems possible to combine t hese two new optical limiting paradigms in single structures which may ther efore be considered as bimechanistic optical power limiters.