Coherent control of photodetachment of H⁻ in an electric field near a metal surface

Abstract

We show that the photodetachment of H⁻ in an electric field near a metal surface can be controlled by using a single or double laser pulse. The method of theoretical analysis used is semi-classical closed orbit theory. The results show that if the period of a certain closed orbit is longer than the pulse width of the single-pulse laser, the contribution of that closed orbit to the photodetachment cross-section will be greatly reduced. As for the double-pulse laser, the pulse width, phase difference and the time delay between the two pulses all play an important role in the photodetachment cross-section. With the decrease of the time delay, the oscillating amplitude of the cross-section increases while the oscillating frequency decreases. Therefore, laser pulses can be used to control the photodetachment process of negative ions or atoms in an external field near metal surfaces.

Keywords:

• closed-orbit theory
• photodetachment
• metal surface
• laser pulse

Acknowledgments

This work is supported by the National Natural Science Foundation of China (Grant No. 11074104 & 10604045), the Higher Educational Science and Technology Program of Shandong Province (Grant No. J09LA02) and the Promotive Research Fund for Young and Middle-aged Scientists of Shandong Province (Grant No. BS2009DX033). We also thank the referees for their good suggestions.