Nonlinear optics near the single photon level with quantum dots coupled to photonic crystals

Low power optical nonlinearities are a crucial requirement for data routing and next generation all-optical processing. The majority of nonlinear optical devices to date exploit weak nonlinearities from a large ensemble of atomic systems, resulting in both high power dissipation and a large device footprint. Quantum dots (QDs) coupled to photonic crystals can provide significant reduction in both device size and power dissipation. The interaction between these two systems creates extremely strong light-matter interaction owing to the tight optical confinement of photonic crystals and large oscillator strengths of QDs. Such interactions enable optical nonlinearities near the single photon level. In this work we investigate the nonlinear properties of QDs coupled to photonic crystals. We demonstrate large optical Stark shift with only 10 photons. We then propose and demonstrate a novel photonic circuit that can route light on a chip with extremely low optical powers.