Focusing of Intense Subpicosecond Laser Pulses in Wedge Targets

TL;DR

This paper uses particle-in-cell simulations to study how ultraintense, short laser pulses are focused in wedge-shaped targets, revealing significant intensity amplification and sustained focusing over femtoseconds.

Contribution

It demonstrates that laser pulses can be focused to near-wavelength scales with amplified intensity in wedge targets, providing a simple model for peak movement and scalability.

Findings

Peak intensity amplified by an order of magnitude

Focusing persists over hundreds of femtoseconds

Performance scales to intensities beyond 10^{20} W/cm^{2}

Abstract

Two dimensional particle-in-cell simulations characterizing the interaction of ultraintense short pulse lasers in the range 10^{18} \leq I \leq 10^{20} W/cm^{2} with converging target geometries are presented. Seeking to examine intensity amplification in high-power laser systems, where focal spots are typically non-diffraction limited, we describe key dynamical features as the injected laser intensity and convergence angle of the target are systematically varied. We find that laser pulses are focused down to a wavelength with the peak intensity amplified by an order of magnitude beyond its vacuum value, and develop a simple model for how the peak location moves back towards the injection plane over time. This performance is sustained over hundreds of femtoseconds and scales to laser intensities beyond 10^{20} W/cm^{2} at 1 \mu m wavelength.