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Electromagnetically induced transparency at a chiral exceptional point


Electromagnetically induced transparency, as a quantum interference effect to eliminate optical absorption in an opaque medium, has found extensive applications in slow-light generation, optical storage, frequency conversion, optical quantum memory and enhanced nonlinear interactions at the few-photon level in all kinds of systems. Recently, there has been great interest in exceptional points, a type of spectral singularity that could be reached by tuning various parameters in open systems, to render unusual features to the physical systems, such as optical states with chirality. Here we theoretically and experimentally study transparency and absorption modulated by chiral optical states at exceptional points in an indirectly coupled resonator system. By tuning one resonator to an exceptional point, transparency or absorption occurs depending on the chirality of the eigenstate. Our results demonstrate a new strategy to manipulate the light flow and the spectra of a photonic resonator system by exploiting a discrete optical state associated with a specific chirality at an exceptional point as a unique control bit. Such an approach is compatible with the state control utilized in quantum gate operation and may open up new avenues for controlling slow light using optical states for optical quantum memory and computing.

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Fig. 1: Indirectly coupled WGM microresonators with manipulation of chirality.
Fig. 2: Level diagrams of indirectly coupled WGM microresonators.
Fig. 3: Absorption at EP with chirality −1.
Fig. 4: Transparency at EP+ with chirality 1.

Data availability

The data represented in Figs. 14 are available in Supplementary Data 14. All other 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 by NSF grant no. EFMA1641109, ARO grant no. W911NF1710189 and DARPA under grant HR00111820042. A.D.S. acknowledges the support of NSF grant no. DMR-1743235. L.J. acknowledges the support of the Packard Foundation (2013-39273).

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Authors and Affiliations



X.J., C.W. and L.Y. conceived the idea and designed the experiments. C.W. and X.J. performed the experiments with help from G.Z. and B.P. C.W. analysed experimental data with help from X.J. and M.Z. Theoretical background and simulations were provided by C.W. with help from M.Z., C.W.H., L.J. and A.D.S. All authors discussed the results and wrote the manuscript. L.Y. supervised the project.

Corresponding author

Correspondence to Lan Yang.

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Supplementary information

Supplementary Information

Supplementary discussion.

Supplementary Data 1

The data corresponding to the graphs in Fig 1.

Supplementary Data 2

The data corresponding to the graphs in Fig 2.

Supplementary Data 3

The data corresponding to the graphs in Fig 3.

Supplementary Data 4

The data corresponding to the graphs in Fig 4.

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Wang, C., Jiang, X., Zhao, G. et al. Electromagnetically induced transparency at a chiral exceptional point. Nat. Phys. 16, 334–340 (2020).

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