Field enhancement of intense laser pulses in a subwavelength plasma aperture

TL;DR

This paper demonstrates through 3D simulations that intense laser pulses can be significantly enhanced in subwavelength plasma apertures, with potential applications in high-intensity plasma-based optical devices.

Contribution

It reveals non-resonant, robust field enhancement in plasma apertures for ultrashort, high-intensity laser pulses, expanding understanding beyond linear regimes.

Findings

Field enhancement is robust across plasma densities above 20n_c.

Energy concentration results from interference between incident and back-scattered fields.

Enhancement is minimally affected by wall thickness.

Abstract

The interaction of intense, ultra-short laser pulses with nanostructures offers promising avenues for spatiotemporal light control. While enhanced optical transmission through subwavelength apertures has been extensively studied in the linear regime, its extension to ultrashort, high-intensity pulses remains largely unexplored. Here we demonstrate, through three-dimensional particle-in-cell simulations, significant field enhancement of intense laser pulses in subwavelength plasma apertures. The enhancement exhibits a non-resonant character, remaining robust across a wide range of plasma densities and saturating above approximately $20n_c$, while showing minimal dependence on wall thickness. Analysis of the Poynting vector reveals that energy concentration arises from interference between the incident field and back-scattered longitudinal field components. This size-dependent enhanced transmission in plasma apertures enables potential applications such as plasma-based dichroic filters operating at extreme intensities.