Intense keV isolated attosecond pulse generation by orthogonally polarized multicycle midinfrared two-color laser field

TL;DR

This paper proposes a method to generate intense keV isolated attosecond pulses using a multicycle midinfrared two-color laser field, leveraging electron trajectory control to produce broad-spectrum humps and isolated pulses without phase compensation.

Contribution

It introduces a novel approach for generating multi-keV isolated attosecond pulses via orthogonally polarized multicycle midinfrared two-color fields, with detailed trajectory analysis.

Findings

Multiple continuum-like humps with broad spectral width are generated.

Intense isolated attosecond pulses are obtained without phase compensation.

The method covers the multi-keV spectral regime using high-energy multicycle pulses.

Abstract

We theoretically investigate the generation of intense keV attosecond pulses in an orthogonally polarized multicycle midinfrared two-color laser field. It is demonstrated that multiple continuum-like humps, which have a spectral width of about twenty orders of harmonics and an intensity of about one order higher than adjacent normal harmonic peaks, are generated under proper two-color delays, owing to the reduction of the number of electron-ion recollisions and suppression of inter-half-cycle interference effect of multiple electron trajectories when the long wavelength midinfrared driving field is used. Using the semiclassical trajectory model, we have revealed the two-dimensional manipulation of the electron-ion recollision process, which agrees well with the time frequency analysis. By filtering these humps, intense isolated attosecond pulses are directly generated without any phase compensation. Our proposal provides a simple technique to generate intense isolated attosecond pulses with various central photon energies covering the multi-keV spectral regime by using multicycle driving pulses with high pump energy in experiment.