Electronically programmable photonic molecule

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Physical systems with discrete energy levels are ubiquitous in nature and are fundamental building blocks of quantum technology. Realizing controllable artificial atom- and molecule-like systems for light would enable coherent and dynamic control of the frequency, amplitude and phase of photons1,2,3,4,5. In this work, we demonstrate a ‘photonic molecule’ with two distinct energy levels using coupled lithium niobate microring resonators and control it by external microwave excitation. We show that the frequency and phase of light can be precisely controlled by programmed microwave signals, using concepts of canonical two-level systems including Autler–Townes splitting, Stark shift, Rabi oscillation and Ramsey interference. Through such coherent control, we show on-demand optical storage and retrieval by reconfiguring the photonic molecule into a bright–dark mode pair. These results of dynamic control of light in a programmable and scalable electro-optic system open doors to applications in microwave signal processing6, quantum photonic gates in the frequency domain7 and exploring concepts in optical computing8 and topological physics3,9.

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Fig. 1: Microwave-controlled photonic molecule.
Fig. 2: Microwave-dressed photonic states.
Fig. 3: Coherent spectral dynamics in the photonic molecule.
Fig. 4: On-demand storage and retrieval of light using a photonic dark mode.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.


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This work was supported in part by National Science Foundation grants (ECCS1609549, DMR-1231319), Office of Naval Research MURI grant N00014-15-1-2761 and the Army Research Laboratory Center for Distributed Quantum Information W911NF1520067, Center for Integrated Quantum Materials (CIQM) and Harvard Office of Technology Development Accelerator. Device fabrication was performed at the Center for Nanoscale Systems at Harvard University.

Author information

M.Z., C.W., S.F. and M.L. conceived the experiment. M.Z., C.W. and A.S.-A. fabricated the devices. M.Z. and Y.H. performed numerical simulations. M.Z., C.W. and T.R. carried out the experiments. M.Z. wrote the manuscript with contribution from all authors. M.L. supervised the project.

Correspondence to Marko Lončar.

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Competing interests

M.Z., C.W. and M.L. are involved in developing lithium niobate technologies at HyperLight Corporation.

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Supplementary information

Supplementary Information

Additional theory and experimental set-up, Supplementary Figures 1–6 and Supplementary References 1–5.

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Zhang, M., Wang, C., Hu, Y. et al. Electronically programmable photonic molecule. Nature Photon 13, 36–40 (2019) doi:10.1038/s41566-018-0317-y

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