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Vol. 18 (2026)

Sub-100 Femtosecond All-Optical Modulation Beyond Electron–Phonon Limits

https://doi.org/10.1007/s40820-026-02166-z
Renxian Gao
College of Physical Science and Technology, Xiamen University, Xiamen 361005, People’s Republic of China
Jiayu Li
Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, Department of Chemistry, Shantou University, Shantou 515063, People’s Republic of China
Xiaoxiang Dong
College of Physical Science and Technology, Xiamen University, Xiamen 361005, People’s Republic of China
Yonglin He
College of Physical Science and Technology, Xiamen University, Xiamen 361005, People’s Republic of China
Wenbin Chen
Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, Department of Chemistry, Shantou University, Shantou 515063, People’s Republic of China
Peiwen Ren
College of Physical Science and Technology, Xiamen University, Xiamen 361005, People’s Republic of China
Xiaoyu Zhao
College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, People’s Republic of China
Ming‑De Li
School of Physics and Optoelectronic Engineering & Guangdong Provincial Key Laboratory of Sensing Physics and System Integration Applications, Guangdong University of Technology, Guangzhou, Guangdong 510006, People’s Republic of China
Zhilin Yang
College of Physical Science and Technology, Xiamen University, Xiamen 361005, People’s Republic of China

Corresponding Author: Zhilin Yang

zlyang@xmu.edu.cn

Nano-Micro Letters, Vol. 18 (2026), Article Number: 315

Abstract

Ultrafast all-optical modulators are central to the advancement of next-generation photonic computing and signal-processing systems. However, the intrinsic electron–phonon relaxation bottleneck in plasmonic materials has long constrained modulation speeds to the picosecond regime, hindering the realization of sub-100 fs modulation. Here, we report a metastructured silver–single-crystal silicon nanodisk antenna that delivers experimentally resolved sub-100 fs all-optical modulation. Distinct from conventional planar metal–semiconductor junctions, the nanodisk architecture spatially co-localizes plasmonic energy deposition with the metal–semiconductor transfer boundary within a nanoscale-confined volume. This configuration markedly shortens hot-carrier transport pathways and preferentially activates interfacial carrier extraction during the earliest relaxation stage, thereby establishing an interface-dominated modulation pathway that precedes electron–phonon thermalization. By enabling modulation on timescales comparable to intrinsic electronic response limits, this work establishes a physical foundation for ultrafast photonic modulation, including femtosecond free-space photonic computing architectures, temporal optical gating, and other ultrafast systems constrained by carrier or cavity lifetimes.


Highlights:
1 Engineered Ag–Si interfacial plasmonic modes enable deconvolution-verified sub-100 fs all-optical modulation, overcoming the temporal bottleneck imposed by electron–phonon relaxation in conventional plasmonic structures.
2 A unified electromagnetic–thermal physical model reveals an interface-governed nonthermal carrier extraction pathway faster than electron–electron and electron–phonon scattering, quantitatively explaining the observed sub-100 fs dynamics.

Keywords

Sub 100 fs all Optical modulation Silver Silicon metastructure; Interfacial hot Carrier dynamics
Gao, Renxian, Jiayu Li, Xiaoxiang Dong, Yonglin He, Wenbin Chen, Peiwen Ren, Xiaoyu Zhao, Ming‑De Li, and Zhilin Yang. 2026. “Sub-100 Femtosecond All-Optical Modulation Beyond Electron–Phonon Limits”. Nano-Micro Letters 18 (April):315. https://doi.org/10.1007/s40820-026-02166-z.
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References
  1. P.L. McMahon, The physics of optical computing. Nat. Rev. Phys. 5(12), 717–734 (2023). https://doi.org/10.1038/s42254-023-00645-5
  2. J. Hu, D. Mengu, D.C. Tzarouchis, B. Edwards, N. Engheta et al., Diffractive optical computing in free space. Nat. Commun. 15(1), 1525 (2024). https://doi.org/10.1038/s41467-024-45982-w
  3. B.J. Shastri, A.N. Tait, T. Ferreira de Lima, W.H.P. Pernice, H. Bhaskaran et al., Photonics for artificial intelligence and neuromorphic computing. Nat. Photonics 15(2), 102–114 (2021). https://doi.org/10.1038/s41566-020-00754-y
  4. Q. Guo, R. Sekine, L. Ledezma, R. Nehra, D.J. Dean et al., Femtojoule femtosecond all-optical switching in lithium niobate nanophotonics. Nat. Photonics 16(9), 625–631 (2022). https://doi.org/10.1038/s41566-022-01044-5
  5. J. Xie, J. Yan, H. Han, Y. Zhao, M. Luo et al., Photonic chip based on ultrafast laser-induced reversible phase change for convolutional neural network. Nano-Micro Lett. 17(1), 179 (2025). https://doi.org/10.1007/s40820-025-01693-5
  6. T.Y. Teo, X. Ma, E. Pastor, H. Wang, J.K. George et al., Programmable chalcogenide-based all-optical deep neural networks. Nanophotonics 11(17), 4073–4088 (2022). https://doi.org/10.1515/nanoph-2022-0099
  7. J. Yang, X. Zhang, Optical fiber delivered ultrafast plasmonic optical switch. Adv. Sci. 8(10), 2100280 (2021). https://doi.org/10.1002/advs.202100280
  8. H. Wang, Z. Hu, J. Deng, X. Zhang, J. Chen et al., All-optical ultrafast polarization switching with nonlinear plasmonic metasurfaces. Sci. Adv. 10(8), eadk3882 (2024). https://doi.org/10.1126/sciadv.adk3882
  9. S. Kunwar, S. Pandit, J.-H. Jeong, J. Lee, Improved photoresponse of UV photodetectors by the incorporation of plasmonic nanops on GaN through the resonant coupling of localized surface plasmon resonance. Nano-Micro Lett. 12(1), 91 (2020). https://doi.org/10.1007/s40820-020-00437-x
  10. M. Ono, M. Hata, M. Tsunekawa, K. Nozaki, H. Sumikura et al., Ultrafast and energy-efficient all-optical switching with graphene-loaded deep-subwavelength plasmonic waveguides. Nat. Photonics 14(1), 37–43 (2020). https://doi.org/10.1038/s41566-019-0547-7
  11. K.F. MacDonald, Z.L. Sámson, M.I. Stockman, N.I. Zheludev, Ultrafast active plasmonics. Nat. Photonics 3(1), 55–58 (2009). https://doi.org/10.1038/nphoton.2008.249
  12. A. Basiri, M.Z.E. Rafique, J. Bai, S. Choi, Y. Yao, Ultrafast low-pump fluence all-optical modulation based on graphene-metal hybrid metasurfaces. Light. Sci. Appl. 11, 102 (2022). https://doi.org/10.1038/s41377-022-00787-8
  13. Q. Guo, Y. Yao, Z.-C. Luo, Z. Qin, G. Xie et al., Universal near-infrared and mid-infrared optical modulation for ultrafast pulse generation enabled by colloidal plasmonic semiconductor nanocrystals. ACS Nano 10(10), 9463–9469 (2016). https://doi.org/10.1021/acsnano.6b04536
  14. A. Schirato, M. Maiuri, A. Toma, S. Fugattini, R. Proietti Zaccaria et al., Transient optical symmetry breaking for ultrafast broadband dichroism in plasmonic metasurfaces. Nat. Photonics 14(12), 723–727 (2020). https://doi.org/10.1038/s41566-020-00702-w
  15. M. Kauranen, A.V. Zayats, Nonlinear plasmonics. Nat. Photonics 6(11), 737–748 (2012). https://doi.org/10.1038/nphoton.2012.244
  16. C. Clavero, Plasmon-induced hot-electron generation at nanop/metal-oxide interfaces for photovoltaic and photocatalytic devices. Nat. Photonics 8(2), 95–103 (2014). https://doi.org/10.1038/nphoton.2013.238
  17. M.L. Brongersma, N.J. Halas, P. Nordlander, Plasmon-induced hot carrier science and technology. Nat. Nanotechnol. 10(1), 25–34 (2015). https://doi.org/10.1038/nnano.2014.311
  18. J.G. Liu, H. Zhang, S. Link, P. Nordlander, Relaxation of plasmon-induced hot carriers. ACS Photonics 5(7), 2584–2595 (2018). https://doi.org/10.1021/acsphotonics.7b00881
  19. M. Taghinejad, H. Taghinejad, Z. Xu, K.-T. Lee, S.P. Rodrigues et al., Ultrafast control of phase and polarization of light expedited by hot-electron transfer. Nano Lett. 18(9), 5544–5551 (2018). https://doi.org/10.1021/acs.nanolett.8b01946
  20. M. Taghinejad, H. Taghinejad, Z. Xu, Y. Liu, S.P. Rodrigues et al., Hot-electron-assisted femtosecond all-optical modulation in plasmonics. Adv. Mater. 30(9), 1704915 (2018). https://doi.org/10.1002/adma.201704915
  21. H. Harutyunyan, A.B.F. Martinson, D. Rosenmann, L.K. Khorashad, L.V. Besteiro et al., Anomalous ultrafast dynamics of hot plasmonic electrons in nanostructures with hot spots. Nat. Nanotechnol. 10(9), 770–774 (2015). https://doi.org/10.1038/nnano.2015.165
  22. L.H. Nicholls, T. Stefaniuk, M.E. Nasir, F.J. Rodríguez-Fortuño, G.A. Wurtz et al., Designer photonic dynamics by using non-uniform electron temperature distribution for on-demand all-optical switching times. Nat. Commun. 10, 2967 (2019). https://doi.org/10.1038/s41467-019-10840-7
  23. G.A. Wurtz, R. Pollard, W. Hendren, G.P. Wiederrecht, D.J. Gosztola et al., Designed ultrafast optical nonlinearity in a plasmonic nanorod metamaterial enhanced by nonlocality. Nat. Nanotechnol. 6(2), 107–111 (2011). https://doi.org/10.1038/nnano.2010.278
  24. M. Taghinejad, W. Cai, All-optical control of light in micro- and nanophotonics. ACS Photonics 6(5), 1082–1093 (2019). https://doi.org/10.1021/acsphotonics.9b00013
  25. H. Liu, W. Dong, H. Wang, L. Lu, Q. Ruan et al., Rewritable color nanoprints in antimony trisulfide films. Sci. Adv. 6(51), eabb7171 (2020). https://doi.org/10.1126/sciadv.abb7171
  26. G.V. Hartland, Optical studies of dynamics in noble metal nanostructures. Chem. Rev. 111(6), 3858–3887 (2011). https://doi.org/10.1021/cr1002547
  27. G. Li, S. Zhang, T. Zentgraf, Nonlinear photonic metasurfaces. Nat. Rev. Mater. 2(5), 17010 (2017). https://doi.org/10.1038/natrevmats.2017.10
  28. M. Abb, Y. Wang, C.H. de Groot, O.L. Muskens, Hotspot-mediated ultrafast nonlinear control of multifrequency plasmonic nanoantennas. Nat. Commun. 5, 4869 (2014). https://doi.org/10.1038/ncomms5869
  29. R. Rouxel, M. Diego, F. Medeghini, P. Maioli, F. Rossella et al., Ultrafast thermo-optical dynamics of a single metal nano-object. J. Phys. Chem. C 124(28), 15625–15633 (2020). https://doi.org/10.1021/acs.jpcc.0c04709
  30. R. Gao, Y. He, D. Zhang, G. Sun, J.-X. He et al., Gigahertz optoacoustic vibration in Sub-5 nm tip-supported nano-optomechanical metasurface. Nat. Commun. 14(1), 485 (2023). https://doi.org/10.1038/s41467-023-36127-6
  31. G. Tagliabue, A.S. Jermyn, R. Sundararaman, A.J. Welch, J.S. DuChene et al., Quantifying the role of surface plasmon excitation and hot carrier transport in plasmonic devices. Nat. Commun. 9(1), 3394 (2018). https://doi.org/10.1038/s41467-018-05968-x
  32. G. Liu, Y. Lou, Y. Zhao, C. Burda, Directional damping of plasmons at metal-semiconductor interfaces. Acc. Chem. Res. 55(13), 1845–1856 (2022). https://doi.org/10.1021/acs.accounts.2c00001
  33. C. Jia, X. Li, N. Xin, Y. Gong, J. Guan et al., Interface-engineered plasmonics in metal/semiconductor heterostructures. Adv. Energy Mater. 6(17), 1600431 (2016). https://doi.org/10.1002/aenm.201600431
  34. R. Sundararaman, P. Narang, A.S. Jermyn, W.A. Goddard III., H.A. Atwater, Theoretical predictions for hot-carrier generation from surface plasmon decay. Nat. Commun. 5, 5788 (2014). https://doi.org/10.1038/ncomms6788
  35. A.M. Brown, R. Sundararaman, P. Narang, W.A. Goddard, H.A. Atwater, Ab initiophonon coupling and optical response of hot electrons in plasmonic metals. Phys. Rev. B 94(7), 075120 (2016). https://doi.org/10.1103/physrevb.94.075120
  36. A. Block, M. Liebel, R. Yu, M. Spector, Y. Sivan et al., Tracking ultrafast hot-electron diffusion in space and time by ultrafast thermomodulation microscopy. Sci. Adv. 5(5), eaav8965 (2019). https://doi.org/10.1126/sciadv.aav8965
  37. M. Bonn, D.N. Denzler, S. Funk, M. Wolf, S.-S. Wellershoff et al., Ultrafast electron dynamics at metal surfaces: competition between electron-phonon coupling and hot-electron transport. Phys. Rev. B 61(2), 1101–1105 (2000). https://doi.org/10.1103/physrevb.61.1101
  38. J. Bin Lee, K. Kang, S.H. Lee, Comparison of theoretical models of electron-phonon coupling in thin gold films irradiated by femtosecond pulse lasers. Mater. Trans. 52(3), 547–553 (2011). https://doi.org/10.2320/matertrans.m2010396
  39. P. Bresson, J.-F. Bryche, M. Besbes, J. Moreau, P.-L. Karsenti et al., Improved two-temperature modeling of ultrafast thermal and optical phenomena in continuous and nanostructured metal films. Phys. Rev. B 102(15), 155127 (2020). https://doi.org/10.1103/physrevb.102.155127
  40. D.G. Cahill, W.K. Ford, K.E. Goodson, G.D. Mahan, A. Majumdar et al., Nanoscale thermal transport. J. Appl. Phys. 93(2), 793–818 (2003). https://doi.org/10.1063/1.1524305
  41. R. Stoner, H. Maris, Kapitza conductance and heat flow between solids at temperatures from 50 to 300 K. Phys. Rev. B 48(22), 16373–16387 (1993). https://doi.org/10.1103/physrevb.48.16373
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