Photo-oxidative tuning of individual and coupled GaAs photonic crystal cavities

We demonstrate a photo-induced oxidation technique for tuning GaAs photonic crystal cavities using a low-power 390 nm pulsed laser. The laser oxidizes a small (< 1 μm) diameter spot, reducing the local index of refraction and blueshifting the cavity. The tuning progress can be actively monitored in real time. We also demonstrate tuning an individual cavity within a pair of proximity-coupled cavities, showing that this method can be used to tune individual cavities in a cavity network, with applications in quantum simulations and quantum computing.