Spatiotemporal addressing of surface activity

We have modified surface catalytic activity in real time and space by focus ing an addressable laser beam to differentially heat a platinum (110) singl e-crystal surface. Ellipsomicroscopy imaging of local conditions (such as r eactant and product local coverages) enabled us to close the loop between s ensing and actuation (both spatiotemporally resolved). Pulses and fronts, t he basic building blocks of patterns, could be formed, accelerated, modifie d, guided, and destroyed at will. Real-time image processing and feedback a llow the design and implementation of new classes of nonlocal evolution rul es.