Experimental Retrieval of Target Structure Information from Laser-Induced Rescattered Photoelectron Momentum Distributions

We have measured two-dimensional photoelectron momentum spectra of Ne, Ar, and Xe generated by 800-nm, 100-fs laser pulses and succeeded in identifying the spectral ridge region (back-rescattered ridges) which marks the location of the returning electrons that have been backscattered at their maximum kinetic energies. We demonstrate that the structural information, in particular the differential elastic scattering cross sections of the target ion by free electrons, can be accurately extracted from the intensity distributions of photoelectrons on the ridges, thus effecting a first step toward laser-induced self-imaging of the target, with unprecedented spatial and temporal resolutions.

Figure 1

Laser-induced photoelectron spectrum for Xe, at laser intensity $1.5\times {10}^{14}\mathrm{W}/{\mathrm{cm}}^2$ at angles 0°, 30°, 60°, and 90°, relative to the polarization vector.

Figure 2

2D photoelectron momentum spectra: (a) for Ne at the laser intensity $3.5\times {10}^{14}\mathrm{W}/{\mathrm{cm}}^2$, (b) for Ar at the laser intensity $2.3\times {10}^{14}\mathrm{W}/{\mathrm{cm}}^2$, (c) for Xe at the laser intensity $1.5\times {10}^{14}\mathrm{W}/{\mathrm{cm}}^2$. The images are plotted in logarithmic scale. The experimental ridge is shown in a dashed circle for each target atom.

Figure 3

Angular distributions of photoelectrons along the BRR compared to the differential elastic scattering cross sections of the target ion: (a) for Ne, (b) for Ar, and (c) for Xe.