3D Alignment by Holding and Spinning Molecules

We introduce a new method for controlling the rotational motion of asymmetric top molecules. The method is capable of producing strong 3-dimensional (3D) alignment, i.e. confine all three principal molecular axes along three orthogonal space fixed axes. The method relies on combining two laser pulses that are short and long with respect to the natural molecular rotational periods. We conclude that strong 3D alignment can be obtained by combining a long and a short laser pulse, linearly polarized orthogonal to each other. Field-free 3D alignment should be experimentally obtainable by rapidly truncating the long laser pulse near the arrival of the short pulse. Our results also indicate 3D alignment revivals from spinning molecules, as the revival times correspond to the rotational constant A.