Delay measurement of attosecond emission in solids

We characterize an attosecond pulse without using a secondary laser pulse. Instead, we use the carrier-envelope-phase dependence of the extreme ultraviolet (XUV) emission to measure the dipole current from a solid material. To confirm, we apply our approach to data derived by solving the time-dependent Schrödinger equation with a periodic potential. Finally, using MgO, we measure the delay shift at the strong XUV absorption feature and explain it as the quantum interference between the continuum and bound states that participate in the generation process.