Signature of quantum interferences in above-threshold detachment of negative ions by a short infrared pulse

Numerical calculations of photodetachment of ${\mathrm{F}}^{-}$ irradiated by a linearly polarized strong short infrared pulse have been performed by evaluating the photoelectron ejection probability in the framework of a Keldysh-type approach modified to account for the temporal behavior of the pulse. The results of the calculations are in good agreement with measurements of energy spectra recently appearing in literature, and show features that may be explained in terms of quantum interferences in time domain.

Figure 1

(Color online) Experimental energy distributions (Ref. 5) of the photoelectrons emitted along (circles) and perpendicular to (crosses) the polarization direction of the pulse electric field compared to the theoretical predictions (solid lines) obtained by averaging Eq. (4) over the spatial laser intensity. Each solid line has been normalized at the highest value of the pertinent experimental result. Laser parameters: peak intensity $1.6\times {10}^{13}\mathrm{W}∕{\mathrm{cm}}^2$, carrier wavelength $1400\mathrm{nm}$.

Figure 2

(Color online) Energy spectra of the photoelectrons emitted along the polarization direction of the laser field. (a) Results of calculations performed by assuming an homogeneous rectangular-shaped laser pulse. The curve has been normalized to its highest value. The dotted curve shows the diffraction function $P_j\left(1\right)$ of Eq. (4); (b) results of calculations obtained by using the sin-square envelope (solid line) defined in Eq. (1) and inhomogeneous (dotted line) pulse. The curve has been normalized to its highest value. Laser parameters as in Fig. 1.

Figure 3

(Color online) (a) As in Fig. 2a and (b) as in Fig. 2b, for photoemission perpendicular to the laser field polarization direction.