Abstract

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. First the most polarizable molecular axis is aligned along a space fixed axis with a long laser pulse (1064 nm, 10 ns, 5×10¹¹ W/cm²). Then the molecules are kicked with a short laser pulse (800 nm, 150 fs, 2×l0¹³ W/cm²) polarized orthogonal to the long pulse. Due to the orthogonal geometry the short pulse interacts only weakly with the most polarizable molecular axis and causes only minor perturbation of the linear alignment; instead it excites rotation about the axis. Subsequent dynamics lead to 3D alignment immediately after the short pulse.

© 2007 IEEE