Simultaneous production of spin-polarized ions/electrons based on two-photon ionization of laser-ablated metallic atoms

Abstract

We demonstrate the simultaneous production of spin-polarized ions/electrons using two-color, two-photon ionization of laser-ablated metallic atoms. Specifically, we have applied the developed technique to laser-ablated Sr atoms, and found that the electron-spin polarization of Sr+ ions, and accordingly, the spin polarization of photoelectrons is 64%±9%, which is in good agreement with the theoretical prediction we have recently reported [T. Nakajima and N. Yonekura, J. Chem. Phys. 117, 2112 (2002)]. Our experimental results open up a simple way toward the construction of a spin-polarized dual ion/electron source.

A scheme to polarize nuclear-spin of atoms by a sequence of short laser pulses: application to the muonium

“…This is because the angular momentum of photons from circularly-polarized pump or probe pulses is redistributed between the spin and orbital angular momenta of photoelectrons as well as photoions. We have experimentally demonstrated spin-polarization of Sr atoms using ns pump and probe pulses [28]. In the second kind, the fine structure of the excited state is not spectrally resolved by the short pump pulse, implying that a coherent superposition of the corresponding manifold is produced.…”

“…Related to the present work, we have proposed a few different schemes to realize spinpolarization of electrons/ions [27][28][29][30][31][32] and nuclei [33,34] using laser pulses. Essentially speaking, we can classify our polarization schemes into two kinds, neither of which, however, utilizes the so-called optical pumping technique, and hence completely different from the present scheme.…”

Investigation of Ultrafast Nuclear Spin Polarization Induced by Short Laser Pulses

“…For example, polarized electrons [5] are highly needed in high-energy physics, while polarized electrons and electron-spin-polarized ions, including neutral atoms and molecules, are useful in surface physics [6] and atomic and molecular physics [7]. Recently we have theoretically as well as experimentally investigated the control of spin polarization of electrons and ions using laser pulses [8][9][10]. In particular, use of the pump and probe laser pulses with short pulse duration has turned out to be a new doorknob to control spin degree of freedom [9][10][11].…”

Control of the spin polarization of photoelectrons/photoions using short laser pulses

“…The essential difference between the single-valence-electron system and a two-valence-electron system presented here is that, for a two-valence-electron system it is not only photoelectrons but also photoions that can be polarized. 6 Furthermore, as we show in this letter, it turned out that, for a multi-valenceelectron system at a certain energy region in the continuum, we can control not only the degree of spin polarization but also its sign simply by changing the time delay between the pump and probe pulses. We should emphasize that this feature is absent for the single-valence-electron system.…”

“…In a series of recent articles, [3][4][5][6] we have investigated the production of spin-polarized electrons through photoionization of atoms. What we have found is that a proper choice of the levels and polarization of nanosecond lasers for excitation and ionization leads to the production of spin-polarized photoelectrons in atomic systems such as Xe and Sr.…”