Stark-induced adiabatic Raman passage examined through the preparation of D-2 (v=2, j=0) and D-2 (v=2, j=2, m=0)

摘要

We study the conditions that must be met for successful preparation of a large ensemble in a specific target quantum state using Stark-induced adiabatic Raman passage (SARP). In particular, we show that the threshold condition depends on the relative magnitudes of the Raman polarizability (r(0v)) and the difference of the optical polarizabilities ((00vj)) of the initial (v = 0, j = 0) and the target (v, j) rovibrational levels. Here, v and j are the vibrational and rotational quantum numbers, respectively. To illustrate how the operation of SARP is controlled by these two parameters, we experimentally prepared D-2 (v = 2, j = 0) and D-2 (v = 2, j = 2, m = 0) in a beam of D-2 (v = 0, j = 0) molecules using a sequence of partially overlapping pump and Stokes laser pulses. By comparing theory and experiment, we were able to determine the Raman polarizability r(02) approximate to 0.3 x 10(-41) Cm/(V/m) and the difference polarizabilities (0020) approximate to 1.4 x 10(-41) Cm/(V/m) and (0022) approximate to 3.4 x 10(-41) Cm/(V/m) for the two Raman transitions. Our experimental data and theoretical calculations show that because the ratio r/ is larger for the (0,0) (2,0) transition than the (0,0) (2,2) transition, much less optical power is required to transfer a large population to the (v = 2, j = 0) level. Nonetheless, our experiment demonstrates that substantial population transfer to both the D-2 (v = 2, j = 0) and D-2 (v = 2, j = 2, m = 0) is achieved using appropriate laser fluences. Our derived threshold condition demonstrates that with increasing vibrational quantum number, it becomes more difficult to achieve large amounts of population transfer.