Diagnosing the electron density of plasma amplifiers using XUV vortex beams

Area of Science:

• Plasma Physics
• Quantum Optics
• Computational Physics

Background:

• High-order harmonics (HOH) generation is a key process in nonlinear optics.
• Orbital angular momentum (OAM) carrying beams offer unique properties for light-matter interactions.
• Inhomogeneous plasmas present complex environments for wave propagation and amplification.

Purpose of the Study:

• To computationally investigate the wavefront of OAM-carrying HOH after amplification in inhomogeneous Ni-like krypton plasmas.
• To explore the potential of using HOH wavefronts as diagnostic tools for plasma characterization.
• To analyze the influence of electron density gradients on the HOH wavefront.

Main Methods:

• Computational simulation of HOH generation and propagation in inhomogeneous plasmas.
• Analysis of wavefront phase curvature using phase jump lines (PJLs) fitting.
• Decomposition of the wavefront into modified Laguerre-Gaussian modes.

Main Results:

• Electron density gradients were shown to induce curvature in the wavefront's phase locus.
• Two distinct methods (PJLs and Laguerre-Gaussian decomposition) were developed for phase curvature analysis.
• The methods successfully recovered plasma information, including density profile, gradient direction, and group velocity.

Conclusions:

• The wavefront of OAM-carrying HOH serves as a sensitive diagnostic for plasma properties.
• This technique offers potential applications in inertial confinement fusion, laboratory astrophysics, and filamentation studies.
• The developed methods provide valuable qualitative and quantitative data on plasma electron density and gradients.