Multiphoton ionization of rare gases by a tunable-wavelength 30-psec laser pulse at 1.06 μm

Abstract

Multiphoton ionization of xenon, krypton, and argon atoms has been investigated by using a tunable-wavelength bandwidth-limited 30-psec laser pulse of ${10}^{13}$ W/${\mathrm{cm}}^{2}$ at 1.06 \ensuremath{\mu}m. The laser linewidth is 0.8 ${\mathrm{cm}}^{\ensuremath{-}1}$, and the laser wavelength can be tuned over a range of 80 \AA{}. No resonant effects have been observed within this wavelength range, although resonance conditions are satisfied. The absence of resonance effects could be explained in terms of the short laser pulse duration. Laser light polarization effects were still measured. Moreover, the ionization energy of krypton has been observed to be lowered by 86\ifmmode\pm\else\textpm\fi{}6 ${\mathrm{cm}}^{\ensuremath{-}1}$ under the influence of a laser electric field of 1.2\ifmmode\times\else\texttimes\fi{}${10}^{8}$ ${\mathrm{Vcm}}^{\ensuremath{-}1}$.