Nano-optical reversible switching of organic photochromes.

Photochromic fulgides are UHV-deposited in ultrathin films exhibiting intrinsic nanostructures. The two isomeric states (C and E) are detected in absorption via scanning near-field optical microscopy (SNOM). The optical image contrast measured in SNOM corresponds to the nanostructure topography observed in atomic force microscopy. Nano-optical reversible switching of individual nanostructures is demonstrated and possible applications to rewritable optical recording on the nanoscale are discussed.