Osnabrück 2002 – scientific programme

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A: Atomphysik

A 1: Multiphotonen I

A 1.6: Talk

Monday, March 4, 2002, 17:45–18:00, HS 15/E10

A detailed comparison of theory and experiment of strong-field photodetachment of negative hydrogen ions — •Rainer Reichle, Hanspeter Helm, and Igor Yu. Kiyan — Fak. Physik, Univ. Freiburg, Germany

H⁻ ions in a keV beam are exposed to 250 fs pulses from an OPA laser operating at 2.15 µ m. An electron imaging technique is used to determine the momentum distributions of the photodetached electrons. The experimental data are compared with the analytical predictions from a KFR-type theory[1]. At intensities ranging up to 1.7× 10¹³ W/cm² excess photon detachment channels up to 4-photons above threshold appear in the spectrum. The short laser pulse duration used circumvents saturation of the lower order detachment channels. In comparing with theory the spatial and temporal distribution of intensities in the laser focus is explicitly taken into acount, as is the kinetic distortion of the electron image due to the motion of target ions. The energy and angular distributions show the predicted quantum interference which arises when electrons of identical momentum are created at different phases of the laser pulse[2]. Research supported by the DFG (SFB 276 TP C14).

[1] G.F. Gribakin and M.Yu. Kuchiev, Phys. Rev. A 55, 3760 (1997).

[2] R. Reichle, H. Helm, I. Yu. Kiyan, Phys. Rev. Lett. 87, 243001 (2001)