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Universal routing of light via optical thermodynamics

Nature Photonics volume 19, pages 1116–1121 (2025)Cite this article

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Abstract

Understanding and exploiting the dynamics of complex nonlinear systems is nowadays at the core of a broad range of scientific and technological endeavours. Within the optical domain, light evolution in a nonlinear multimode environment presents a formidable problem, as its chaotic evolution often hinders predictive insights. Recently, an optical thermodynamic framework has been put forward that, in a systematic manner, can not only predict but also harness the intricate behaviour of these systems. By deploying entropic principles, here we demonstrate a counter-intuitive optical process in which light, launched into any input port of a judiciously designed nonlinear array, universally channels into a tightly localized ground state, a response that is completely unattainable in linear conservative arrangements. This phenomenon arises from the interplay between lattice structure and the way the kinetic and nonlinear Hamiltonian components unfold, leading to two optical thermal processes: Joule–Thomson-like expansion followed by mode thermalization. Experimentally, this effect is demonstrated in properly configured nonlinear time-synthetic mesh lattices, where the optical temperature approaches near zero, causing light to condense at a single spot, regardless of the initial excitation position. The effect demonstrated here opens new avenues for applying the principles of optical thermodynamics in realizing new optical functionalities, such as all-optical beam-steering, multiplexing and nonlinear beam-shaping in high-power regimes, while also offering a greater understanding of the notable physics of light–matter interactions in multimode nonlinear systems.

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Fig. 1: Nonlinear funnelling of light.
Fig. 2: Thermodynamic principle of light-funnelling.
Fig. 3: Experimental observation of universal light-funnelling.
Fig. 4: Regime of optical funnelling.

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Data availability

Source data are provided with this paper. All other data supporting the plots and findings within this paper are available from the corresponding authors upon request.

Code availability

The numerical codes used in this study (MATLAB) are available upon request from the corresponding authors.

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Acknowledgements

This research was partially supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering (Award No. DE-SC0025224 for developing the theory and building the experimental set-up to H.M.D., A.M.B.B., M.A.S., H.R., G.G.P., D.N.C. and M.K.), Army Research Office (Grant No. W911NF-23-1-0312 to H.M.D., A.M.B.B., M.A.S., H.R., G.G.P., D.N.C. and M.K.), the Air Force Office of Scientific Research (AFOSR) Multidisciplinary University Research Initiative (MURI) (Award No. FA9550-20-1-0322 for novel light–matter interactions in topologically non-trivial Weyl semimetal structures and systems to H.M.D., A.M.B.B., M.A.S., H.R., G.G.P., D.N.C. and M.K.), ONR MURI (Award No. N00014-20-1-2789 for the classical entanglement of light to H.M.D., A.M.B.B., M.A.S., H.R., G.G.P., D.N.C. and M.K.), AFOSR MURI (Award No. FA9550-21-1-0202 for programmable systems with non-Hermitian quantum dynamics to H.M.D., A.M.B.B., M.A.S., H.R., G.G.P., D.N.C. and M.K.), Department of Energy (Grant No. DESC0022282 to M.A.S., H.R., G.G.P. and D.N.C.), W. M. Keck Foundation (M.A.S., H.R., G.G.P. and D.N.C.), the MPS Simons collaboration (Simons Grant No. 733682 to M.A.S., H.R., G.G.P. and D.N.C.), US Air Force Research Laboratory (Grant No. FA86511820019 to M.A.S., H.R., G.G.P. and D.N.C.), and fellowships from the University of Southern California (H.M.D. and A.M.B.B.).

Author information

Author notes

  1. These authors contributed equally: Hediyeh M. Dinani, Georgios G. Pyrialakos.

Authors and Affiliations

  1. Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA, USA

    Hediyeh M. Dinani, Georgios G. Pyrialakos, Abraham M. Berman Bradley, Huizhong Ren, Mahmoud A. Selim, Demetrios N. Christodoulides & Mercedeh Khajavikhan

  2. Abbe Center of Photonics, Friedrich Schiller University Jena, Jena, Germany

    Monika Monika & Ulf Peschel

  3. Department of Physics and Astronomy, University of Southern California, Los Angeles, CA, USA

    Demetrios N. Christodoulides & Mercedeh Khajavikhan

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  1. Hediyeh M. Dinani
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Contributions

G.G.P., H.M.D., D.N.C. and M.K. developed the idea. H.M.D. and G.G.P. performed the simulations. H.M.D. and A.M.B.B. built the set-up, and H.M.D. performed the experiments. All authors contributed to the analysis of the results and preparation of the paper.

Corresponding authors

Correspondence to Demetrios N. Christodoulides or Mercedeh Khajavikhan.

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Nature Photonics thanks Tsampikos Kottos, Maxim Shcherbakov and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Information

Supplementary Figs. 1–13 and Discussion Sections 1–13.

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Source data for all experimental figures presented in the main text.

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Dinani, H.M., Pyrialakos, G.G., Berman Bradley, A.M. et al. Universal routing of light via optical thermodynamics. Nat. Photon. 19, 1116–1121 (2025). https://doi.org/10.1038/s41566-025-01756-4

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