Coherent control of photodetachment of H- in perpendicular electric and magnetic fields

Using the semiclassical closed orbit theory, we study the coherent control of the photodetachment of H- by a single and double-pulse laser in perpendicular electric and magnetic fields. Theoretically, dependences of calculated cross section on laser pulse widths, time delays, relative phases and the classical detached electron's closed orbit period are presented and discussed in detail. The results suggest that for the single pulse laser, if the pulse width is shorter than the particular closed orbit period, then the contribution of that closed orbit to the photodetachment cross section is reduced. While for the double pulse laser, the cross section not only depends on the pulse width, but also depends on the time delay and the relative phase of the two pulses. If the pulse delay time equals to the period of one closed orbit, then the contribution of that orbit becomes significant. Therefore, we can use the pulse laser to control the photodetachment process of ion or atom in external fields. © 2009 Chinese Physical Society and IOP Publishing Ltd.