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Multiphoton electron emission with non-classical light


Photon number distributions of classical and non-classical light sources have been studied extensively, yet their impact on photoemission processes is largely unexplored. In this article, we present measurements of electron number distributions from metal needle tips illuminated with ultrashort light pulses with various photon quantum statistics. By varying the photon statistics of the exciting light field between classical (Poissonian) and quantum (super-Poissonian), we demonstrate that the measured electron distributions are changed substantially. Using single-mode bright squeezed vacuum light, we measure extreme statistics events with up to 65 electrons from one light pulse at a mean of 0.27 electrons per pulse—the likelihood for such an event equals 10−128 with Poissonian statistics. By changing the number of modes of the exciting bright squeezed vacuum, we can tailor the electron number distribution on demand. Most importantly, our results demonstrate that the photon statistics is imprinted from the driving light to the emitted electrons, opening the door to new sensor devices and to strong-field optics with quantum light and electrons.

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Fig. 1: Experimental scheme.
Fig. 2: Electron number statistics with coherent excitation light.
Fig. 3: Electron number statistics with BSV as excitation light.

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Data availability

Source data are provided with this paper. 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 research was supported by the European Research Council (Consolidator Grant NearFieldAtto and Advanced Grant AccelOnChip) and the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Project ID 429529648–TRR 306 QuCoLiMa (ʻQuantum Cooperativity of Light and Matterʼ) and Sonderforschungsbereich 953 (ʻSynthetic Carbon Allotropesʼ), Project ID 182849149. Furthermore, this research was supported by the Gordon and Betty Moore Foundation, Grant ID 11473. J.H. acknowledges funding from the Max Planck School of Photonics.

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Authors and Affiliations



J.H. and A.M. measured the electron number distributions with non-classical light. J.H., S.M. and H.H. measured the distributions with the coherent light source. J.H. and A.M. analysed the data and generated the plots. I.K., M.C. and P.H. conceived the experiment. All authors contributed to writing the manuscript.

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Correspondence to Jonas Heimerl or Peter Hommelhoff.

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Nature Physics thanks Peter Baum and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Extended data

Extended Data Fig. 1 The influence of an additional electron emission process on electron-number statistics.

(a) Electron-number distribution for single-mode fourth-order Gamma distribution (blue) for an average of μ = 1 electrons per laser pulse, calculated from Eq. (2) (see main text). Lines are guide to the eye. (b)-(d) Blue are the distributions from (a). Orange are Poisson distributions corresponding to mean numbers of electrons (b) μ = 0.01, (c) μ = 0.1 and (d) μ = 0.5. The yellow curves are the corresponding convolutions of the Gamma distribution and the Poisson distribution. For increasing Poissonian admixture we observe a clear deviation from the original distribution in (a).

Extended Data Fig. 2 The influence of the number of modes.

Influence of number of modes m = 1, 5, 20, 40, 80 on the generalized Gamma distribution for (a) linear case (n = 1) and (b) the non-linear case (n = 4). for the same mean value of μe = 48. The blue dashed line represents the Poissonian case in both cases.

Source data

Source Data Fig. 2

Probability distributions of the shown curves.

Source Data Fig. 3

Probability distributions of the shown curves.

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Heimerl, J., Mikhaylov, A., Meier, S. et al. Multiphoton electron emission with non-classical light. Nat. Phys. 20, 945–950 (2024).

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