Isolated short attosecond pulse generation by a spatially inhomogeneous combined field

We present a theoretical investigation of high-order harmonics and isolated short attosecond pulse generation by a spatially inhomogeneous combined field. The calculation results show that this spatiotemporally synthesized field can not only extend the spectral cutoff but also realize the quantum path control, whereupon an ultrawide supercontinuum with a smooth and regular structure is generated. By filtering a wide range of continuous harmonics around the cutoff region, an isolated 17.6 as pulse with a bandwidth of 279 eV is directly obtained without any phase compensation. Moreover, we also investigate the influence of the CEP, time delay, spatial nonhomogeneity, and laser intensity on the harmonic spectrum.