Radiation Pressure Acceleration of Ion Beams Driven by Circularly Polarized Laser Pulses

TL;DR

This paper demonstrates that circularly polarized ultra-high contrast laser pulses can effectively accelerate fully ionized carbon ions via radiation pressure, with experimental and simulation evidence showing phase-stable acceleration in ultra-thin DLC foils.

Contribution

It provides the first experimental and simulation evidence of phase-stable radiation pressure acceleration of ions using circular polarization.

Findings

Circular polarization reduces electron heating.

Optimal foil thickness is around 5.3 nm.

C6+ ions are dominantly accelerated by radiation pressure.

Abstract

We present experimental studies on ion acceleration from ultra-thin diamond-like carbon (DLC) foils irradiated by ultra-high contrast laser pulses of energy 0.7 J focussed to peak intensities of 5*10^{19} W/cm^2. A reduction in electron heating is observed when the laser polarization is changed from linear to circular, leading to a pronounced peak in the fully ionized carbon spectrum at the optimum foil thickness of 5.3 nm. Two-dimensional particle-in-cell (PIC) simulations reveal, that those C^{6+} ions are for the first time dominantly accelerated in a phase-stable way by the laser radiation pressure.