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Giant nonlinear optical responses from photon-avalanching nanoparticles


Avalanche phenomena use steeply nonlinear dynamics to generate disproportionately large responses from small perturbations, and are found in a multitude of events and materials1. Photon avalanching enables technologies such as optical phase-conjugate imaging2, infrared quantum counting3 and efficient upconverted lasing4,5,6. However, the photon-avalanching mechanism underlying these optical applications has been observed only in bulk materials and aggregates6,7, limiting its utility and impact. Here we report the realization of photon avalanching at room temperature in single nanostructures—small, Tm3+-doped upconverting nanocrystals—and demonstrate their use in super-resolution imaging in near-infrared spectral windows of maximal biological transparency. Avalanching nanoparticles (ANPs) can be pumped by continuous-wave lasers, and exhibit all of the defining features of photon avalanching, including clear excitation-power thresholds, exceptionally long rise time at threshold, and a dominant excited-state absorption that is more than 10,000 times larger than ground-state absorption. Beyond the avalanching threshold, ANP emission scales nonlinearly with the 26th power of the pump intensity, owing to induced positive optical feedback in each nanocrystal. This enables the experimental realization of photon-avalanche single-beam super-resolution imaging7 with sub-70-nanometre spatial resolution, achieved by using only simple scanning confocal microscopy and without any computational analysis. Pairing their steep nonlinearity with existing super-resolution techniques and computational methods8,9,10, ANPs enable imaging with higher resolution and at excitation intensities about 100 times lower than other probes. The low photon-avalanching threshold and excellent photostability of ANPs also suggest their utility in a diverse array of applications, including sub-wavelength imaging7,11,12 and optical and environmental sensing13,14,15.

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Fig. 1: PA mechanism in Tm3+-doped nanocrystals.
Fig. 2: Demonstration of nanoparticle PA.
Fig. 3: Modifying PA kinetics via ANP shell thickness, surface-to-volume ratio and Tm3+ content.
Fig. 4: PA single-beam super-resolution imaging.

Data availability

All data generated or analysed during this study, which support the plots within this paper and other findings of this study, are included in this published article and its Supplementary InformationSource data are provided with this paper.

Code availability

The code for modelling the PA behaviour using the differential rate equations described in the Supplementary Information are freely available at


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P.J.S., Y.D.S., S.H.N. and C.L. gratefully acknowledge support from the Global Research Laboratory (GRL) Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (number 2016911815), and KRICT (KK2061-23, SKO1930-20). Y.D.S. acknowledges the Industrial Strategic Technology Development Program (number 10077582) funded by the Ministry of Trade, Industry, and Energy (MOTIE), Korea. E.Z.X. gratefully acknowledges support from the NSF Graduate Research Fellowship Program. Y.L. was supported by a China Scholarship Council fellowship. A.T. was supported by the Weizmann Institute of Science − National Postdoctoral Award Program for Advancing Women in Science. Work at the Molecular Foundry was supported by the Office of Science, Office of Basic Energy Sciences, of the US Department of Energy under contract number DE-AC02-05CH11231. K.Y. acknowledges support from Programmable Quantum Materials, an Energy Frontier Research Center funded by the US Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), under award DE-SC0019443. A.B. acknowledges financial support from NCN, Poland, grant number UMO-2018/31/B/ST5/01827.

Author information




P.J.S., E.M.C., B.E.C., C.L. and Y.D.S. conceived the study. Experimental measurements and associated analyses were conducted by C.L., E.Z.X., Y.L., A.T., K.Y., A.F.-B., S.H.N. and E.M.C. Advanced nanoparticle synthesis and characterization was performed by Y.L., A.T. and E.M.C. Theoretical modelling and simulations of PA photophysics were carried out by C.L., E.M.C., A.T., A.M.K. and A.B. Advanced simulations of super-resolution imaging were performed by A.M.K. and A.B. All authors contributed to the preparation of the manuscript.

Corresponding authors

Correspondence to Yung Doug Suh or Artur Bednarkiewicz or Bruce E. Cohen or Emory M. Chan or P. James Schuck.

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The authors declare no competing interests.

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Peer review information Nature thanks Xueyuan Chen, Andries Meijerink and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.

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This file includes: Supplementary Figures 1 to 13, Supplementary Tables 1 to 11, Supplementary Methods, Supplementary Discussion and Supplementary References.

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Lee, C., Xu, E.Z., Liu, Y. et al. Giant nonlinear optical responses from photon-avalanching nanoparticles. Nature 589, 230–235 (2021).

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