Creation and phase control of molecular coherences using pulsed magnetic fields

Jet-cooled CS2 molecules were pumped by a nanosecond UV laser pulse into a rotational level of an electronically excited state. After a delay, the deg enerate magnetic sublevels of this rotational state were subjected to a seq uence of tailored magnetic field pulses B-Z(t), which split the Zeeman leve ls and thereby created coherences. The time evolution of these superpositio n states was monitored by the quantum beat method. In the presence of an ad ditional static magnetic field B-Y perpendicular to the pulsed field B-Z(t) , control and manipulation of the generated coherences could be further ext ended. This work demonstrates the versatility of this technique where the B -Z(t) pulse length, pulse amplitude, the timing of the pulses and their mut ual delay provide flexibility in creating, controlling and manipulating sup erposition states in molecules.