Giant non-linearities of organic based crystals

The non-linear effects of organic based crystals in which the Frenkel type of excitons are realized were studied. Using the non-equilibrium Green function method it is shown that significant non-linearities can arise in such type of crystals at moderate pump intensities owing to interaction of excitons. The study of transmission the intensive quasiresonant electromagentic wave by crystal showed that at natural (non-linear) boundary condition the multistability effects can arise with very sharp and big change of transmission. The switching devices similar to optical key can be realized. (C) 1999 Elsevier Science B.V. All rights reserved.