Single zeptosecond pulse generation from muonic atoms with nonlinear chirped laser pulses

We propose a new scheme for the generation of single zeptosecond pulses by using a one-dimensional muonic hydrogen atom model. Owing to the large mass of the muon, the muonic atoms can survive much stronger fields, which causes a very broad plateau in the high-order harmonic spectrum. By solving a one-dimensional time-dependent Schrodinger equation, the high-order harmonic spectrum of the muonic atom in super-intense nonlinear chirped laser pulses is obtained. It is found that the harmonic spectrum is greatly affected by the chirp rate parameters of the laser field. By adjusting the chirp rate parameters, an ultra-broad super-continuum spectrum could be obtained, from which a single zeptosecond pulse could be generated without phase compensation.