Slow light on a chip via atomic quantum state control


The ability to slow down the propagation of light touches both fundamental aspects of light–matter interactions and practical applications in photonic communication and computation1,2,3. Optical quantum interference can substantially reduce the speed of light while offering additional dramatic optical effects based on the ability to control electronic quantum states4,5. Recent efforts are increasingly being directed towards harnessing these effects in integrated photonic structures6,7. Here, we report the first demonstration of slow light and electromagnetically induced transparency in a self-contained, planar atomic spectroscopy chip. Using hot rubidium atoms in hollow-core waveguides, we demonstrate 44% optical transparency with a group index of 1,200, or more than sevenfold slower light than in photonic-crystal waveguides8. Optical pulse delays of 16 ns with a delay-bandwidth product of 0.8 are observed. This implementation of atomic quantum state control in integrated photonic structures will enable coherent photonics at ultralow power levels.

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Figure 1: Integrated atomic spectroscopy platform.
Figure 2: Electromagnetically induced transparency (EIT) on a chip.
Figure 3: Slow light on a chip.
Figure 4: Slow light propagation characteristics.


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We thank A. Gaeta, S.E. Harris, J. Lowell, S. Knappe and J. Kitching for helpful discussions. We acknowledge support through the nanocharacterization lab in the W.M. Keck Center for Nanoscale Optofluidics at University of California Santa Cruz and financial support by the Defense Advanced Research Projects Agency (DARPA) Defense Sciences Office Slow-Light Program (Air Force Office of Scientific Research contract #FA9550-05-1-0432) and the National Science Foundation under grants ECS-0500602 and ECS-0500670.

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B.W., J.F.H., A.R.H. and H.S. conceived and designed the experiments. J.F.H., K.H. and E.J.L. fabricated the atomic spectroscopy chips. B.W. performed the atomic spectroscopy experiments. B.W. and H.S. analysed the spectroscopy data, and H.S., A.R.H., B.W. and J.F.H. prepared the manuscript.

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Correspondence to Holger Schmidt.

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The authors declare no competing financial interests.

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Wu, B., Hulbert, J., Lunt, E. et al. Slow light on a chip via atomic quantum state control. Nature Photon 4, 776–779 (2010).

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