Ultraintense femtosecond magnetic nanoprobes induced by azimuthally polarized laser beams

TL;DR

This paper introduces a novel method using azimuthally polarized laser beams to generate ultrafast, intense, and spatially isolated magnetic fields for probing magnetic nanodomains on femtosecond timescales.

Contribution

The study demonstrates a new scheme to produce intense, isolated magnetic fields using structured laser beams, supported by simulations and an analytic model, with potential applications in magnetic nanodomain control.

Findings

Achieved magnetic fields up to 4 Tesla with a $10^{11}$ W/cm$^2$ laser.

Isolated magnetic fields extend over micrometer distances.

Enhanced magnetic field strength by a factor of approximately 6.

Abstract

We report a novel scheme to generate laser-induced, ultrafast, intense (Tesla scale), spatially isolated, magnetic fields. Three-dimensional particle-in-cell simulations show that a femtosecond azimuthally-polarized infrared vector beam, aimed to a conducting circular aperture, produces an intense axially polarized tip-shaped femtosecond magnetic field, extending over micrometer distances and being isolated from the electric field. Our results are backed-up by an analytic model, demonstrating the underlying physics and guiding for optimal parameters. In particular, we find the conditions under which the magnetic nanoprobe is substantially enhanced, reaching 4 T when driven by a $10^{11}$ W/cm$^2$ laser field, which reflects a selective enhancement by a factor of $\sim$6. Our scheme offers a promising tool to control, probe and tailor magnetic nanodomains in femtosecond timescales through pure magnetic interaction by using structured laser beams.