Slow light in two dimensional semi-conductor photonic crystals

We report on the combination of slow light propagation with the resonanceproperties of a photonic crystal cavity and with the slow mode of a photonic crystalwaveguide.We demonstrate theoretically and experimentally that slow light induced by theCoherent Population Oscillation (CPO) effect enables to have small-size and ultra-high quality (Q) factor cavity, regardless of the technological and design issues.The experimental proof is performed in an L3 2D PhC cavity with semiconductorquantum wells as active, medium in which the CPO effect is induced. We achieve acavity Q-factor of 520000 which corresponds to an enhancement 138 comparing tothe original Q-factor of the cavity.We present a theoretical approach to the combination of CPO-based slow lightand slow mode in PhC waveguides, showing that the total group index is a multi-plication of the group indices associated respectively to the CPO slow light and tothe waveguide slow mode. We also set the basis for the experimental demonstra-tion by designing and fabricating samples in the clean room facilities of LPN andaddressing the challenging issue of coupling and extracting light in and from thewaveguides. A particular design of the PhC in the waveguide is issued as a gratingthat allows to couple light perpendicularly to the plane of the PhC from free space.The vertical coupler has also been designed and fabricated along the waveguide andhas been experimentally characterized. Slow light based on CPO effect in the PhCwaveguides is always under experimental investigation.