Coherent phase control of population transfer through ladder system in two laser pulses with ω and nω

Abstract

The ladder transitions controlled by two harmonic pulses are investigated theoretically using a time-dependent quantum wave packet method for the ground electronic state of HF molecule. By choosing [Formula: see text], [Formula: see text] and [Formula: see text] schemes, the population can be transferred to target states [Formula: see text]. The population distribution can be controlled by the average amplitude of total electric field which depends on the relative phase of two pulses. With the variation of the relative phase between [Formula: see text] and [Formula: see text] pulses, the variation of population has a period of [Formula: see text]. For [Formula: see text] and [Formula: see text] schemes, the population distributions show oscillation behavior with a period of [Formula: see text] by varying the relative phase. The two harmonic pulses can realize a nearly complete population transfer to the target state.

Effect of phase coherence on population transfer in three harmonic laser pulses

“…For ( 3 w w + ) pulse scheme, the phase of 3rd-harmonic pulse has no effect on the symmetry and the final population distribution has a period of 2p. Besides the Brumer-Shapiro transition scheme, the two harmonic pulses can also control the population transfer through a ladder transition scheme, in which the initial, intermediate, and target states are respectively coupled by two harmonic pulses and population is transferred to the target state via the intermediate state [27,32]. If the Brumer-Shapiro and ladder transition schemes occur simultaneously in a process of population transfer, the two transition schemes will affect each other, which can increase the effect of pulse phases on population distribution.…”