Observations of temporal group delays in slow-light multiple coupled photonic crystal cavities

We demonstrate temporal group delays in coherently coupled high- Q multicavity photonic crystals, in an all-optical analog to electromagnetically induced transparency. We report deterministic control of the group delay up to 4× the single cavity lifetime in our room-temperature chip. Supported by three-dimensional numerical simulations and theoretical analyses, our multipump beam approach enables control of the multicavity resonances and intercavity phase, in both single and double transparency peaks. The standing-wave wavelength-scale photon localization allows direct scalability for chip-scale optical pulse trapping and coupled-cavity quantum electrodynamics.