Recent advances in ultrashort intense laser pulse technology allows for
unprecedented study of laser matter interaction on the time scale of a few
optical cycles [1]. For few cycle pulses the electric
field, E(t)=Eo(t) cos(?t+?) depends strongly on the phase ? of the carrier
wave of frequency ? with respect to the pulse envelope Eo(t). ? is called
the carrier envelope phase, CEP. Spatiotemporal variation of
electromagnetic pulses E(t) consisting of very few cycles are now precisely
known and can be shaped with attosecond precision via control over
?.
We have previously demonstrated by numerical simulations that intense few
cycle laser pulses produce asymmetries in strong-field ionization of one
electron atomic 3-D model systems [2] and that such asymmetry follows a
universal CEP dependence which can be used to measure the duration of
subfemtosecond pulses [3]. We investigate in the present work double
ionization in a 2-D model of H2 and HeH+ and its dependence on CEP
effects. The 2-D model allows for calculation of the angular dependence of
the double electron ejection by intense 800 nm laser pulses in molecules
and to compare to recent experimental results in Ar atoms [4]. Comparisons
are also made at large internuclear distances where Charge Resonance
Enhanced Ionization, CREI, dominates [5].
[1] T. Brabec, F. Krausz, Rev. Mod. Phys. 72, 545 (2000).
[2] S. Chelkowski, A.D. Bandrauk, A. Apolonski, Phys. Rev. A71, 053815
(2005); Opt. Lett. 29, 1557 (2004).
[3] A.D. Bandrauk, S. Chelkowski, H.S. Nguyen, Phys. Rev. A68, 041802
(2003).
[4] X. Liu et al., Phys. Rev. Lett. 93, 263001 (2004).
[5] G. Lagmago Kamta, A.D. Bandrauk, Phys. Rev. Lett. 94, 203003 (2005).
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