Improving molecular orientation by optimizing relative delay and intensities of two-color laser pulses

Abstract

We numerically explore molecular orientation dynamics with moderately intense nanosecond two-color laser pulses. It is believed that the nanosecond two-color pulse can adiabatically control the molecular orientation. However, in our simulation based on the time-dependent Schrodinger equation, which naturally includes nonadiabatic effects, the orientation dynamics shows clear deviations from the adiabatic approximation (AA) results, while the molecular alignment dynamics is in good agreement with the AA results. The nonadiabaticity is significantly influenced by three parameters, the intensities, and the relative delay of the two wavelengths. In this work, we clarify the reason behind the nonadiabaticity and provide the solutions for achieving higher degrees of orientation