Compression of attosecond water window pulse by stacked Cr/Sc multilayer mirror with chirped structure

An attosecond water window pulse generated from high harmonics spectrum is chirped, and needs to be compressed to transform limited pulse by chirp compensation. In this paper, a Cr/Sc-stacked multilayer with chirped structure is proposed for attosecond pulse compression. Three stacked multilayer mirrors are designed to compress chirped attosecond pulses covering 300–400 eV water window spectrum. Nearly, transform limited attosecond pulses are all obtained after reflected by the stacked multilayer mirrors, which exhibit 0.27%, 0.41%, and 0.58% average reflectivity and − 2086, − 3481 or − 5644 as2 average group delay dispersion in the 300–400 eV region, respectively. The research proposes a stacked multilayer mirror for chirp compensation and pulse compression, which could be used for pulse shaping of an attosecond water window pulse.