High-order harmonic generation by sub-cycle laser pulses and associated scaling laws

TL;DR

This paper investigates high-harmonic generation using sub-cycle laser pulses interacting with helium atoms, deriving scaling laws and producing attosecond pulses through detailed analysis and modeling.

Contribution

It introduces a precise modeling of sub-cycle pulses with a complex source vector beam and derives new scaling laws for harmonic yield and cutoff energy.

Findings

Harmonic cutoff extends with shorter pulse durations due to blueshift.

Scaling laws relate harmonic yield and cutoff to pulse parameters.

Generated attosecond pulses of approximately 100 as duration.

Abstract

We studied the high-harmonic generation by the interaction of sub-cycle laser pulses with the He atom. The sub-cycle pulses are modeled using the complex source vector beam model, which is an exact solution to Maxwell's equations and accurately models the sub-cycle field profiles. We observed that the harmonic cutoff could be extended with the variation of the sub-cycle pulse duration, mainly because of the inherent blueshift associated with shorter pulses. The scaling laws for the harmonic yield and harmonic cutoff energy with pulse duration and fundamental driver wavelengths are also deduced. Furthermore, a detailed wavelet analysis of harmonic generation by sub-cycle pulses is carried out. The appropriate filtering and superposition of the harmonics gave rise to a single attosecond pulse of duration ~ 100 as.