Engineered atom-light interactions in 1D photonic crystals*

Nano- and microscale optical systems offer efficient and scalable quantum interfaces through enhanced atom-field coupling in both resonators and continuous waveguides. Beyond these conventional topologies, new opportunities emerge from the integration of ultracold atomic systems with nanoscale photonic crystals. One-dimensional photonic crystal waveguides can be engineered for both stable trapping configurations and strong atom-photon interactions,\footnote{C.-L. Hung, \textit{et al.}, New J. Phys. \textbf{15}, 083026 (2013).} enabling novel cavity QED and quantum many-body systems,\footnote{D. E. Chang \textit{et al.}, New J. Phys. \textbf{14}(6), 063003 (2012).} as well as distributed quantum networks. We present the experimental realization of such a nanophotonic quantum interface based on a nanoscale photonic crystal waveguide, demonstrating a fractional waveguide coupling of $\Gamma_{1D}/\Gamma'$ of $0.32\pm 0.08$, where $\Gamma_{1D}$ ($\Gamma'$) is the atomic emission rate into the guided (all other) mode(s).\footnote{A. Goban et al., arXiv:1312.3446 (2013).} We also discuss progress towards intra-waveguide trapping of ultracold Cs.