Materials and devices for ultrafast all-optical processing

Molecular photonics, information processing based on strong interactions of photons and molecules, has attracted much attention, since it can fully utilize many superior properties of both photons and molecules. We have been developing materials showing ultrafast absorption changes in the visible to near infrared regions by photoinduced electron transfer and reverse reactions or by excited electronic state formation. Guided wave mode (GWM) geometry composed of a prism, a metal thin film, and a photoresponsive polymer film successfully achieved sensitive, all optical, and very fast control of reflectance by transient or persistent changes of GWM conditions by means of photoinduced complex refractive index changes upon nanosecond to femtosecond laser excitation. All-optical parallel control of reflected probe light by pump (writing) light was demonstrated by photochromic spiropyran or fulgide, and various metallophthalocyanines dispersed in appropriate polymers.