Tomography of asymmetric molecular orbitals with a one-color inhomogeneous field.

We demonstrate image asymmetric molecular orbitals via high-order harmonic generation in a one-color inhomogeneous field. Due to the broken inversion symmetry of the inhomogeneous field in space, the returning electrons with energy in a broad range can be forced to recollide from only one direction for all the orientation angles of molecules, which therefore can be used to reconstruct asymmetric molecular orbitals. Following the procedure of molecular orbital tomography, the highest occupied molecular orbital of carbon monoxide (CO) is satisfactorily reconstructed with high-order harmonic spectra driven by the inhomogeneous field. This scheme is helpful to relax the requirement of laser conditions and is also applicable to other asymmetric molecules.