In situ optofluidic control of reconfigurable photonic crystal cavities

The mobile nature of fluids is fully exploited in planar photonic crystals to not only tune and reconfigure in situ optical microcavities, in a continuous and reversible manner, but also to create "a posteriori" spatially programmable cavities. Both the amount of liquid and the location of the selectively infiltrated area can be accurately controlled either mechanically, using a microfiber manipulator, or optically, using a laser-controlled evaporation and recondensation scheme. The wide applicability is illustrated by tuning a cavity resonance over 50¿nm, adjusting the frequency splitting of an originally degenerate cavity mode, and by freely moving a liquid-induced cavity through dragging a microdroplet