  We have investigated the angle-resolved ATI spectrum of oriented molecules in
the IR+XUV co-rotating circular laser fields. According to the different roles
of IR and XUV laser in the ionization process, we purposefully adjust the
photon energy of XUV and the intensity of IR laser to make the ionization
spectrum of the molecule distributed in a suitable momentum region. Moreover,
under the same laser conditions, the background fringes in the ionization
spectrum of the molecule can be removed by using the ionization spectrum of the
atom with the same ionization energy as the molecule, so that the molecular
orbital density distribution in the suitable momentum region can be obtained.
That is, for any unknown molecule, as long as the ionization energy of the
molecule can be measured, the density distribution of the molecular orbital can
be imaged in a definite momentum region by adjusting the laser field
conditions, which may shed light on the experimental detection of molecular
orbitals.
