Unveiling the Inhomogeneous Nature of Strong Field Ionization in Extended Systems.

Area of Science:

• Atomic and Molecular Physics
• Plasma Physics
• Nanoscale Science

Background:

• Intense laser interaction with atomic clusters leads to ion emission with distinct spatial patterns.
• Understanding these patterns is crucial for controlling energetic ion production.

Purpose of the Study:

• To investigate the influence of laser wavelength on ion emission energy and anisotropy from argon clusters.
• To elucidate the underlying mechanisms of inhomogeneous ionization and nanoplasma formation.

Main Methods:

• Experimental setup involving wavelength-tunable lasers and argon clusters.
• Classical molecular dynamics simulations to model cluster ionization and nanoplasma evolution.

Main Results:

• Ion emission energy and anisotropy are tunable via laser wavelength.
• Shorter wavelengths yield isotropic and energetic emissions; longer wavelengths produce increasingly anisotropic emissions.
• A columnlike charge distribution, driven by the cluster's dipole response, was identified as a key factor in anisotropic emission.

Conclusions:

• Laser wavelength is a critical parameter for controlling ion emission characteristics from atomic clusters.
• The identified inhomogeneous ionization mechanism provides a new understanding of anisotropic ion emission.
• These findings have implications for nanostructure and complex molecule interactions with intense light.