Microfluidic photonic crystal double heterostructures

We demonstrate postprocessed and reconfigurable photonic crystal double-heterostructure cavities via selective fluid infiltration. We experimentally investigate the microfluidic cavities via evanescent probing from a tapered fiber at telecommunication wavelengths. Fabry-Pérot fringes associated with modes of the induced cavity are in good agreement with the theory. We also demonstrate a cavity with quality factor $Q=4300$⁠. Our defect-writing technique does not require nanometer-scale alterations in lattice geometry and may be undertaken at any time after photonic crystal waveguide fabrication.