Multiple Phase Stepping Generation in Alkali Metal Atoms: A Comparative Theoretical Study

Abstract

We theoretically demonstrated optical phase switches in light storage-like experiments. Typical light storage (LS) and retrieval experiments consist of the probe field in the probe channel with writing and reading fields across the drive branch, as well as its recovery. The probe and first drive pulses as the standard electromagnetically induced transparency (EIT) effect of storing light are used in the proposed scheme for the atomic excitations. A train of probe pulses is used after a short storage period to induce Raman gain in the drive channel. The proposed scheme was applied to alkali-metal atoms such as 23Na, 87Rb, and 39K vapours. Spatiotemporal phase variations for generated drive pulses were found to shape in the form of discrete phase distributions. The proposed approach in the process of obtaining phase discrete distributions for different irradiation intensities was tested. For weak fields, the discrete distributions were distinct as a result of the differences in the upper hyperfine structure (hf) and the atomic relaxations. However, for moderate fields, the discrete phase distributions are smeared by the atomic relaxations.

Influence of Frequency-Sweep on Discrete and Continuous Phase Distributions Generated in Alkali-Metal Vapours

“…The initial temporal pulse profiles for the probe and drive were assumed to be Gaussian. In this study, we truncated the initial interaction time to contain only two probe fields instead of three, as was carried out in [1,2]. Furthermore, we kept the domain of the time-axis the same.…”

“…In this section, we analyse a double-lambda configuration with a two-colour excitation of 87 Rb atoms within the D 1 line, i.e., 5s 2 S 1/2 − 5p 2 P 1/2 [2]. The bar states can be described in terms of the generic four states: |1〉 = |5 2 S 1/2 (F g = 1)〉; |2〉 = |5 2 S 1/2 (F g = 2)〉; |3〉 = |5 2 P 1/2 (F e = 1)〉; and |4〉 = |5 2 P 1/2 (F e = 1)〉, where F g (F e ) stands for the total angular momentum associated with ground and excited hyperfine states.…”

“…In recent papers, we have studied the temporal profile associated with the phases of dual-colour pulses, such as the drive and the probe train in a double-lambda system composed of the hyperfine states of alkali atoms with a nuclear spin (I = 3/2) [1,2]. The field's phases were shown to form temporal discrete distributions such as square waves.…”