Water window attosecond sources generation by using the multi-cycle time-delay two circularly polarized pulses

Abstract

In this paper, a promising scheme is proposed to generate the water window isolated attosecond pulses from the high-order harmonics by using the multi-cycle time-delay two circularly polarized pulses. The results show that with the introduction of delay time of the two pulses, not only the harmonic cutoff is extended, but also the modulation on the harmonic spectrum is suppressed. Especially for the [Formula: see text] nm, [Formula: see text] nm and the [Formula: see text] nm two cases, a 341 eV and a 502 eV supercontinua including the whole water window region are obtained. Finally, by properly superposing the harmonics in the supercontinua regions, a series of sub-34as wavelength-tunable attosecond pulses in the water window region can be obtained.