Ultrafast Near-Field Dynamics in Silver Nanowires Driven by Few-Cycle Short-Wave Infrared Pulses

Area of Science:

• Plasmonics
• Nanophotonics
• Ultrafast Optics

Background:

• Time-resolved imaging of plasmonic near fields is established for visible light.
• Exploration in the short-wavelength infrared (SWIR) range is limited.
• Understanding SWIR plasmon dynamics is crucial for advanced photonic applications.

Purpose of the Study:

• To visualize ultrafast plasmon dynamics in silver nanowires at SWIR wavelengths.
• To investigate the influence of nanowire geometry on plasmonic behavior.
• To explore the potential of silver nanowires as SWIR field concentrators.

Main Methods:

• Utilized time-resolved photoemission electron microscopy (TR-PEEM).
• Employed few-cycle SWIR pulses to drive plasmon dynamics.
• Performed electromagnetic simulations and time-dependent linear modeling.

Main Results:

• Observed strong, cycle-synchronized electric-field enhancement at nanowire ends.
• Found variations in local intensity and temporal response within and between nanowires.
• Demonstrated that nanowire length and end morphology significantly impact plasmon dynamics and field enhancement.
• Identified suppression of substrate-induced modes by nonlinear photoemission from nanowire ends.
• Noted a lower-than-expected power-law dependence of photoemission yield, hinting at strong-field effects.

Conclusions:

• Silver nanowires act as efficient local SWIR field concentrators.
• TR-PEEM successfully images tunable ultrafast plasmonic responses in the SWIR.
• These findings open avenues for nanoscale photonic applications and ultrafast electron emission control.