Exploring control landscapes for laser-driven molecular fragmentation

The growing success of quantum optimal control experiments has been attributed to the favorable topology of the control landscape, which specifies the functional relationship between the physical objective and the control variables describing the applied field. This work explores experimental control landscapes expressing the yields of dissociative ionization products from halogenated hydrocarbons in terms of three control variables specifying a polynomial expansion of the spectral phase of the ultrafast laser pulse. Many of the landscapes in this work exhibit features predicted by control landscape theory, including a lack of suboptimal extrema, i.e., traps and the presence of connected optimal level sets, i.e., continuously varying values of the control variables that produce an optimal objective yield. Placing significant constraints on the control resources, particularly by limiting the laser pulse energy, was found to distort the underlying landscape topology. The control landscapes from a diverse, yet related family of halogenated hydrocarbons are shown to possess similar features, reflecting the chemical similarity of the compounds. (C) 2013 AIP Publishing LLC.