Subcycle interference dynamics of time-resolved photoelectron holography with midinfrared laser pulses

Time-resolved photoelectron holography from atoms using midinfrared laser pulses is investigated by solving the corresponding time-dependent Schrödinger equation (TDSE) and a classical model, respectively. The numerical simulation of the photoelectron angular distribution of Xe irradiated with a low-frequency free-electron laser source agrees well with the experimental results. Different types of subcycle interferometric structures are predicted by the classical model. Furthermore with the TDSE model it is demonstrated that the holographic pattern is sensitive to the shape of the atomic orbitals. This is a step toward imaging by means of photoelectron holography.

Figure 1

Schematic illustration of interference trajectories in photoelectron holography. Trajectory S${}_1$: after tunnel ionization, the electron is accelerated in the laser field, then driven back and scattered by the core. Trajectory S${}_2$: the ionized electron oscillates in the laser field without being scattered.

Figure 2

Comparison of experimental (a) and theoretical (b) photoelectron momentum distribution of Xe. The initial state is the metastable 6$s$ state, the laser intensity is $I=7.1\times {10}^{11}$ W/cm${}^2$, and the wavelength is 7 $\mu$m.

Figure 3

Sketch of different subcycle interference trajectories and the corresponding interferometric structures. The laser parameters are the same as in Fig. 2. In the upper panel, A stands for the signal electron, B represents the reference electron.

Figure 4

Sketch of time double-slit interference trajectories and the corresponding interferometric structures by the classical model. Laser parameters are the same as in Fig. 2. A stands for the signal electron; B represents the reference electron.

Figure 5

Atomic orbitals of H in momentum space and the corresponding photoelectron momentum distribution in a laser field with intensity $I=1.775\times {10}^{11}$ W/cm${}^2$ and wavelength 7 $\mu$m. The initial state is (a) 3$s$, (b) 3$p$, and (c) 3$d$. The horizontal (red) line corresponds to the cutoff momentum of the directly ionized electrons.