Acoustic modes of single nanostructures

Plasmonic nanostructures with high quality acoustic oscillations have great promise for applications in biosensing, opto-mechanics, and mass spectrometry. An impulsive lattice heating via a cascade of electron-electron and electron-phonon relaxations after plasmon excitation of a metallic nanoparticle using an ultrafast laser pulse creates a coherent density change of the particle; for example, in the breathing mode the density changes in the radial direction. Anisotropic particles have additional acoustic modes, while particle-substrate coupling creates new higher order acoustic modes.

The Link Research Group focuses on understanding these coherent acoustic oscillations on the single particle level, completely free from ensemble averaging, and their relationship to the extrinsic and intrinsic properties of the nanoparticle. The acoustic coupling of a single particle to the surrounding environment or a nearby particle influences the quality of the acoustic mode, opening up intriguing possibilities to design, fabricate, and optically characterize single nanoscale oscillators. The Link Research Group is specifically pursuing a deeper understanding of how acoustic modes depend on the nanoparticle structure and interfacial contact.

Selected publications:

  1. N. Gross, M. Madadi, B. Ostovar, P. D. Dongare, L. A. McCarthy, W.-Y. Chiang, W.-S. Chang, N. J. Halas, C. F. Landes, J. E. Sader, and S. Link, Strong Substrate Binding Modulates the Acoustic Quality Factors in Gold Nanodisks, J. Phys. Chem. C, 127, 10, 5054-5066 (2023)
  2. M.-N. Su, B. Ostovar, N. Gross, J. E. Sader, W.-S. Chang, and S.Link, Acoustic Vibrations and Energy Dissipation Mechanisms for Lithographically Fabricated Plasmonic Nanostructures Revealed by Single-Particle Transient Extinction Spectroscopy, J. Phys. Chem. C, 125 (3), 1621 (2021)
  3. C. Yi, M.-N. Su, P. D. Dongare, D. Chakraborty, Y.-Y. Cai, D. M. Marolf, R. N. Kress, B. Ostovar, L. J. Tauzin, F. Wen, W.-S. Chang, M. R. Jones, J. E. Sader, N. J. Halas, and S. Link, Polycrystallinity of Lithographically Fabricated Plasmonic Nanostructures Dominates Their Acoustic Vibrational Damping, Nano Lett., 18 (6), 3494 (2018)
  4. W.-S. Chang, F. Wen, D. Chakraborty, M.-N. Su, Y. Zhang, B. Shuang, P. Nordlander, J. E. Sader, N. J. Halas, and S. Link, Tuning the acoustic frequency of a gold nanodisk through its adhesion layer, Nat. Comm., 6, 7022 (2015)