Time-resolved photodynamics of triangular-shaped silver nanoplates

Area of Science:

• Nanophotonics and Plasmonics
• Materials Science
• Ultrafast Spectroscopy

Background:

• Silver nanoparticles exhibit surface plasmon resonance, a phenomenon sensitive to their physical properties.
• Understanding nanoparticle dynamics at ultrafast timescales is crucial for developing advanced optical materials.

Purpose of the Study:

• To investigate the ultrafast mechanical vibrations of triangular silver nanoparticles following plasmon excitation.
• To identify the specific vibrational modes and their excitation mechanisms.

Main Methods:

• Femtosecond laser excitation of plasmon resonance in triangular silver nanoparticles.
• Spectroscopic analysis to detect spectral modulations indicative of mechanical vibrations.
• Development and application of a variational elastodynamic model for theoretical analysis.

Main Results:

• A bimodal mechanical vibration signature was observed after fast electron relaxation.
• The two lowest frequency, totally symmetric vibrational modes were identified as responsible for spectral modulation.
• The model accurately predicted the influence of these vibrations on plasmon peak position and width.

Conclusions:

• Thermal expansion and electron pressure are the primary drivers for exciting the observed bimodal vibrations.
• The study provides a comprehensive understanding of nanoparticle mechanical responses to optical excitation.