Generation of subcycle isolated attosecond pulses by pumping ionizing gating

TL;DR

This paper introduces a novel pumping ionizing gating (PIG) method that uses a plasma grating and a counterpropagating pump pulse to generate isolated attosecond pulses with high intensity and efficiency from long picosecond laser pulses.

Contribution

The paper presents a new scheme for generating isolated attosecond pulses using plasma gratings and resonant reflection, enabling high-intensity pulses from longer pump pulses.

Findings

Generated 330 as pulses with 33 times pump intensity

Achieved around 0.1% conversion efficiency

Demonstrated feasibility with 3D simulations

Abstract

We present a novel approach named as pumping ionizing gating (PIG) for the generation of isolated attosecond pulses (IAPs). In this regime, a short laser is used to ionize a pre-existing gas grating, creating a fast-extending plasma grating(FEPG) having an ionization front propagating with the velocity of light. A low-intensity long counterpropagating pump pulse is then reflected by a very narrow region of the ionization front, only where the Bragg conditions for resonant reflection is satisfied. Consequently, the pump reflection is confined within a sub-cycle region called PIG, and forms a wide-band coherent IAP in combination with the frequency up-conversion effect due to the plasma gradient. This approach results in a new scheme to generate IAPs fromlong picosecond pump pulses. Three-dimensional (3D) simulations show that a 1.6-ps, 1-{\mu}m pump pulse can be used to generate a 330 as laser pulse with a peak intensity approximately 33 times that of the pump and a conversion efficiency of around 0.1%.These results highlight the potential of the PIG method for generating IAPs with high conversion efficiency and peak intensity.