Exceptionally Large Third-Order Optical Nonlinearity of the Organic Charge-Transfer Complex

Much effort has been devoted to a search for material having a large third-order optical nonlinearity sufficient to realize ultra-fast optical signal processing and optical computing etc. π-conjugated organic materials, especially conductive polymers such as polydiacetylenes, seem to attract a principal interest in this field because of their fast responces and large optical nonlinearities.1) Those known materials put origin of their optical nonlinearities on intramolecular electronic polarization. Our own scope is, however, that supramolecular electronic polarization is possibly an efficient origin of optical nonlinearity.2)