High-efficiency water-window x-ray generation from nanowire array targets irradiated with femtosecond laser pulses

TL;DR

This paper reports a significant enhancement in water-window soft x-ray generation using polyethylene nanowire array targets irradiated with femtosecond laser pulses, achieving high energy conversion efficiency supported by simulations.

Contribution

It introduces a novel nanowire array target method that substantially improves water-window x-ray emission efficiency compared to planar targets.

Findings

Over tenfold increase in x-ray emission from nanowire targets

Maximum energy conversion efficiency of 0.5%/sr achieved

Longer nanowires yield higher x-ray emission efficiency

Abstract

We demonstrate the high-efficiency generation of water-window soft x-ray emissions from polyethylene nanowire array targets irradiated by femtosecond laser pulses at the intensity of 4*10^19 W/cm^2. The experimental results indicate more than one order of magnitude enhancement of the water-window x-ray emissions from the nanowire array targets compared to the planar targets. The highest energy conversion efficiency from laser to water-window x-rays is measured as 0.5%/sr, which comes from the targets with the longest nanowires. Supported by particle-in-cell simulations and atomic kinetic codes, the physics that leads to the high conversion efficiency is discussed.