Plasmon excitation under extreme-intensity laser pulses

Plasmon excitation is crucial for controlling and localizing electromagnetic (EM) fields far below the diffraction limit. However, in the high-intensity regime, the possibility of exciting plasmons and their dynamics is poorly understood. In this domain, conventional linear models are insufficient to explain plasmon dynamics as the strength of the EM field is comparable to inter-atomic binding forces, and a more detailed description is needed. In this work, we numerically investigate plasmon excitation and its dynamics using particle-in-cell (PIC) simulation under high-intensity laser pulses (10¹² – 10¹⁶ Wcm^‒2). In the limit of low intensities, we observe plasmon excitation, which correlates well with linear modes. As the intensity increases, we find that the plasmonic field significantly affects electron dynamics and ionization of atoms. The findings indicate that plasmons are well suited for taming high-energy light-matter interaction.