Closed-form solutions for the production of ions in the collisionless ionization of gases by intense lasers

Physical Review A (Impact Factor: 2.81). 06/1993; 47(5):4193-4203. DOI: 10.1103/PhysRevA.47.4193
Source: PubMed


We derive in closed form the solutions to the rate equations for sequential field ionization of gases by a focused laser beam. We obtain the low-intensity and the high-intensity limits of the ion yield for each charge state produced by the laser pulse. Furthermore we derive the scaling laws for the appearance intensity and the saturation intensity of the ion yield. We find that the appearance intensity depends not only on the binding energy of the ionized electron but also on the quantum numbers of the shell from which the electron ionizes. We interpret this dependence on the quantum number to be the species dependence in the appearance intensities discussed by Meyerhofer and co-workers [Phys. Rev. Lett. 63, 2212 (1989)]. Formulas for five ionization models are presented.

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    • "In order to show the explicit dependence of the cutoff photon energy on the atomic and laser parameters, we derived a simple formula based on (1) to predict [17], [18] (2) where and are in eV, 0.5 (to correct an approximation in the derivation of the analytical expression), is the laser wavelength in m, and is the FWHM of the pulse in fs. Here, is the ionization probability for defining the saturation intensity (which is chosen to be 0.98 for our calculation), is the effective principle quantum number and can be found in reference [17]. "
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    ABSTRACT: We report experimental and theoretical results on high-harmonic generation with 25-fs laser excitation pulses. The shortest wavelength we observe, at 2.7 nm, is well within the “water window” region of X-ray transmission. In the case of all the noble gases, we obtain excellent agreement between theoretical predictions for the highest harmonic photon energy generated and our experimental observations. We also obtain excellent agreement between theory and experiment for the highest photon energy generated as a function of laser pulsewidth between 25 and 100 fs. Finally, we observe that the individual harmonic peaks near the cutoff are well resolved for positively chirped pump pulses, but are unresolved in the case of negatively chirped excitation pulses
    IEEE Journal of Selected Topics in Quantum Electronics 04/1998; 4(2-4):266 - 270. DOI:10.1109/2944.686731 · 2.83 Impact Factor
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    ABSTRACT: Ionisation and dissociative ionisation of CS2 by intense 532 nm radiation in the intermediate regime between tunnelling and multiphoton ionisation has been studied. The relative intensities of S+, C+ and CS+2 have been measured as a function of laser intensity over the range 4 × 1012−7 × 1013 W cm−2, S+ ions have a significantly lower saturation intensity than C+ and CS+2. Comparison of the respective ionisation energies indicates that the intense laser field dissociates CS2 first, and the fragments are subsequently ionised.
    Chemical Physics Letters 01/1994; 217(5):626-630. DOI:10.1016/0009-2614(93)E1435-J · 1.90 Impact Factor
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