5 research outputs found
A Dynamic 'Double Slit' Experiment in a Single Atom
A single-atom 'double-slit' experiment is realized by photo-ionizing Rubidium
atoms using two independent low power lasers. The photoelectron wave of
well-defined energy recedes to the continuum either from the 5P or 6P states in
the same atom, resulting in two-path interference imaged in the far field using
a photoelectron detector. Even though the lasers are independent and not phase
locked, the transitions within the atom impart the phase relationship necessary
for interference. The experiment is designed so that either 5P or 6P states are
excited by one laser, before ionization by the second beam. The measurement
cannot determine which excitation path is taken, resulting in interference in
wave-vector space analogous to Young's double-slit studies. As the lasers are
tunable in both frequency and intensity, the individual excitation-ionization
pathways can be varied, allowing dynamic control of the interference term.
Since the electron wave recedes in the Coulomb potential of the residual ion, a
quantum model is used to capture the dynamics. Excellent agreement is found
between theory and experiment.Comment: 8 pages, 4 figures, accepted in Phys. Rev. Let
Natural & unnatural-parity contributions in electron-impact ionization of laser-aligned atoms
Differential cross section measurements from laser-aligned Mg atoms are compared to theoretical calculations using both time dependent and time-independent formalisms. It is found that both natural and unnatural parity contributions to the calculated cross sections are required to emulate the data when the state is aligned out of the scattering plane
Comparison of experiment and theory for superelastic electron-collision studies from laser-aligned magnesium
A combined experimental and theoretical study of superelastic electron collisions from laser-aligned magnesium atoms for a range of collision energies from 35 to 55 eV is presented. 24Mg atoms were excited from the 3 1S0 ground state to the 3 1P1 excited state using continuous-wave linearly polarized laser radiation at ∼285 nm. Electrons of well-defined energy Einc then deexcited the targets, and the superelastically scattered electrons emerging from the collision were detected as a function of scattering angle and laser polarization. Results for alignment of the target by the electron beam are presented for a range of scattering angles, for outgoing energies from Eout=35 to 55 eV. The agreement between the measurements and the results of the convergent close-coupling theory are encouraging, but some discrepancies remain