Active spatial control of plasmonic fields

The field of plasmonics1 offers a route to control light fields with metallic nanostructures through the excitation of surface plasmon polaritons2. These surface waves, bound to a metal dielectric interface, can tightly confine electromagnetic energy3. Active control over surface plasmon polaritons has potential for applications in sensing4, photovoltaics5, quantum communication6, 7, nanocircuitry8, 9, metamaterials10, 11 and super-resolution microscopy12. We achieve here active control of plasmonic fields using a digital spatial light modulator. Optimizing the plasmonic phases through feedback, we focus surface plasmon polaritons at a freely prechosen point on the surface of a nanohole array. Digital addressing and scanning of surface plasmon polaritons without mechanical motion may enable novel interdisciplinary applications of advanced plasmonic devices in cell microscopy, optical data storage and sensing.