Ultrafast Nuclear Spin Polarization by Short Laser Pulses

Abstract

We propose a novel scheme to realize ultrafast nuclear spin polarization by short laser pulses. Combined use of the hyperfine interaction and the static electric field is the key for that. The idea is specifically applied to various isotopes of alkaline‐earth atoms, Mg and Ca, with nuclear spin I = 1/2, 3/2, 5/2, and 7/2. After the detailed theoretical analysis, we find that spin‐polarization as high as 88%, 66%, 33%, and 25%, respectively, for I = 1/2, 3/2, 5/2, and 7/2, can be attained in the time scale of a few to tens of ns, which is at least 2–3 orders of magnitude shorter than any known optical methods. Due to this ultrafast nature, our scheme is applicable not only for stable nuclei but also unstable nuclei with a lifetime as short as a few μs.