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The vibrational modes of semiconductor and metal nanostructures occur in the MHz to GHz frequency range, depending on dimensions. These modes are at the heart of nano-optomechanical devices, and understanding how they dissipate energy is important for applications of the devices. In this paper ultrafast transient absorption microscopy has been used to examine the breathing modes of a single gold nanoplate, where up to four overtones were observed. Analysis of the frequencies and amplitudes of the modes using a simple continuum mechanics model shows that the system behaves as a free plate, even though it is deposited onto a surface with no special preparation. The overtones decay faster than the fundamental mode, which is not predicted by continuum mechanics calculations of mode damping due to radiation of sound waves. Possible reasons for this effect include frequency dependent thermoelastic effects in the nanoplate, and/or flow of acoustic energy out of the excitation region.
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This content will become publicly available on January 22, 2026
The Science of Nanostructure Acoustic Vibrations
Ultrafast excitation of nanoparticles can excite the acoustic vibrational modes of the structure that correlate with the expansion coordinates. These modes are frequently seen in transient absorption experiments on metal nanoparticle samples and occasionally for semiconductors. The aim of this review is to give an overview of the physical chemistry of nanostructure acoustic vibrations. The issues discussed include the excitation mechanism, how to calculate the mode frequencies using continuum mechanics, and the factors that control vibrational damping. Recent results that demonstrate that the high frequencies inherent to the acoustic modes of nanomaterials trigger a viscoelastic response in surrounding liquids are also discussed, as well as vibrational coupling between nanostructures and mode hybridization within the nanostructures. Mode hybridization provides a way of manipulating the lifetimes of the acoustic modes, which is potentially useful for applications such as mass sensing.
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- Award ID(s):
- 2002300
- PAR ID:
- 10530425
- Editor(s):
- Goodson, Theodore; McCoy, Anne B
- Publisher / Repository:
- Annual Reviews
- Date Published:
- Journal Name:
- Annual Review of Physical Chemistry
- ISSN:
- 0066-426X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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