Synthetic Dimensions

Synthetic dimensions are formed by coupling states spanned by an internal photonic degree of freedom (e.g. frequency, polarization), or by engineering additional spatiotemporal mode structure on the electromagnetic field (e.g. transverse modes, orbital angular momentum, ultrashort temporal pulses). The concept of a synthetic dimension originated in cold atoms, where the spin states of the atom were used to mimic a discrete spatial lattice for conveniently studying artificial gauge fields, quantum Hall effects, and extra-dimensional physics. Since a single waveguide or resonator can support a very large number of these modes along one or more synthetic dimensions, compact footprints are achievable. In other words, a device that would take many waveguides or resonators if one used spatial (real-space) encoding, can be achieved in a device that occupies much less space, if one uses synthetic dimensions. Additionally, a single, suitably engineered high-speed arbitrary waveform can couple multiple modes simultaneously over a long range, not being limited by the nearest-neighbor coupling of real-space architectures, thus drastically reducing the number of electronic/optical control signals. These benefits, combined with the dynamic reconfigurability of synthetic-space photonic circuits, holds promise to repurpose the same structure for a wide range of functionalities, essentially building a nanophotonic FPGA within just a single or a few waveguides.

The concept of synthetic dimensions is especially attractive for topological physics, nonreciprocal devices, quantum simulation, quantum computing, and scalable neural networks.

Tutorials and reviews

Original research papers from our work

  • A. Dutt, Q. Lin, L. Yuan, M. Minkov, M. Xiao, and S. Fan, “A single photonic cavity with two independent physical synthetic dimensions,” Science 367, 59 (2020). [Quantum Hall effects, Topological physics]
  • K. Wang*, A. Dutt*, K. Y. Yang, C. C. Wojcik, J. Vučković, and S. Fan, “Generating arbitrary topological windings of a non-Hermitian band,” Science 371, 1240 (2021). [Non-Hermitian topological physics]
  • K. Wang, A. Dutt, C. C. Wojcik, and S. Fan, “Topological complex-energy braiding of non-Hermitian bands,” Nature 598, 59 (2021). [Non-Hermitian topological physics]
  • G. Li*, Y. Zheng*, A. Dutt*, D. Yu, Q. Shan, S. Liu, L. Yuan, S. Fan, X. Chen, “Dynamic band structure measurement in the synthetic space,” Science Advances 7, eabe4335 (2021).
  • S. Buddhiraju, A. Dutt, M. Minkov, I. A. D. Williamson, and S. Fan, “Arbitrary linear transformations for photons in the frequency synthetic dimension,” Nat Commun 12, 2401 (2021). [For neural networks and quantum computing]
  • C. Leefmans*, A. Dutt*, J. Williams, L. Yuan, M. Parto, F. Nori, S. Fan, and A. Marandi, “Topological Dissipation in a Time-Multiplexed Photonic Resonator Network,” arXiv:2104.05213 (2021). [Topological physics, driven-dissipative models]
  • B. Bartlett, A. Dutt, and S. Fan, “Deterministic photonic quantum computation in a synthetic time dimension,” arXiv:2101.07786 (2021). (in press, Optica) [Quantum computing]
  • A. Dutt, M. Minkov, I.A.D. Williamson, S. Fan, “Higher-order topological insulators in synthetic dimensions,” Light: Science & Applications 9, 131 (2020). [topological physics]
  • L. Yuan, A. Dutt, M. Qin, S. Fan, X. Chen, “Creating locally interacting Hamiltonians in the synthetic frequency dimension for photons,” Photon. Research 8, B8 (2020). [interacting topological physics, analog quantum simulation, quantum nonlinear optics]
  • C. Joshi, A. Farsi, A. Dutt, B.Y. Kim, X. Ji, Y. Zhao, A. Bishop, M. Lipson, A.L. Gaeta, “Frequency domain quantum interference with entangled photons from an integrated microresonator,” Phys. Rev. Lett. 124, 143601 (2020). [quantum nonlinear optics]
  • A. Dutt, M. Minkov, Q. Lin, L. Yuan, D. A. B. Miller, S. Fan, “Experimental band structure spectroscopy along a synthetic dimension,” Nature Communications 10, 3122 (2019). [topological physics]