Generation of intense single short attosecond pulse with a multicycle spatially inhomogeneous field
We theoretically study the high order harmonics and single attosecond pulse generation from a pre excited He+ ion in a multicycle two color spatially inhomogeneous field. It is shown that the broadband supercontinuum spectrum and single quantum path selection can be realized, and then a single 15.2 as pulse is directly obtained. By appending a uv attosecond pulse to the two color spatially inhomogeneous field at a proper time, the conversion efficiency of the high energy part of the supercontinuum is improved by at least an order of magnitude, which enables the production of an intense single 17.3 as pulse.