Sub-50 attosecond pulse generation from multicycle nonlinear chirped pulses

TL;DR

This paper introduces a method to generate isolated sub-50 attosecond pulses using multi-cycle nonlinear chirped laser pulses, leveraging symmetry breaking in high-order harmonic generation to produce broad spectra.

Contribution

The study demonstrates a robust technique for attosecond pulse generation that is effective regardless of the laser pulse length or chirp form.

Findings

Broad continuum spectrum enables sub-50 attosecond pulse creation

Method is effective with various laser pulse lengths and chirp configurations

Produces nearly isolated attosecond pulses through symmetry breaking

Abstract

We present a method of producing single attosecond pulses by high-order harmonic generation with multi-cycle nonlinear chirped driver laser pulses. The symmetry of the laser feld in several optical cycles near the pulse center is dramatically broken, and then the photons which cover a much broad spectrum burst almost only in one optical cycle. So an ultra-broad continuum spectrum appears in the high order harmonic spectrum, from which an isolated sub-50 attosecond pulse could be obtained. The results are almost independent of the length and chirp form of the driver laser pulse.