Spin flip in ionization of highly charged ions (Vol. 45 No.3)

The qualitatively different behavior of spin in strong laser fields, within SFA (left) and the proposed theory (right). Spin effects in the tunneling regime of ionization are built up in three steps: spin precession in the bound state, during tunneling, and during the motion in continuum. Only the last two steps are included in SFA. The red, blue and green arrows indicate the initial spin, the spin after the tunneling, and the final spin, respectively. The spin quantization axis is along the laser propagation direction.

How does the electron’s spin evolve during atomic ionization in a strong laser field? A new theoretical result obtained by the authors shed light on this relativistic quantum phenomenon. It was shown that even if an electron is very tightly bound by the strong Coulomb field in a highly charged ion, the spin dynamics may still be crucially affected by a strong laser field of relatively moderate intensity, see figure. This effect is beyond the commonly accepted Strong-Field-Approximation (SFA) and can be confirmed in a challenging experiment employing collisions of highly charged ions with ultra-strong laser beams.

M. Klaiber, E. Yakaboylu, C. Müller, H. Bauke, G. G. Paulus and K. Z. Hatsagortsyan, “Spin dynamics in relativistic ionization with highly charged ions in super-strong laser fields”, J. Phys. B: At. Mol. Opt. Phys., 47, 065603 (2014)