Polymorphic nanoparticles as all-optical memory elements.

A nanoparticle undergoing light-induced transformations between structural phases with different optical properties is an inheritably bistable structure and this bistability can be used to create a resonator-free optical memory element, operating at very low power levels. We experimentally demonstrate this memory functionality using a film of gallium nanoparticles, and we present a method for differentially accessing the logic state of the memory using a modulated optical probe beam.