Probing Molecular Dynamics by Laser-Induced Backscattering Holography

We use differential holography to overcome the forward scattering problem in strong-field photoelectron holography. Our differential holograms of H-2 and D-2 molecules exhibit a fishbonelike structure, which arises from the backscattered part of the recolliding photoelectron wave packet. We demonstrate that the backscattering hologram can resolve the different nuclear dynamics between H-2 and D-2 with subangstrom spatial and subcycle temporal resolution. In addition, we show that attosecond electron dynamics can be resolved. These results open a new avenue for ultrafast studies of molecular dynamics in small molecules.