Theoretical analysis on two-photon absorption spectroscopy in a confined four-level atomic system

V. A. Khodovoǐ, N. A. Chigir

李院院 Yuanyuan Li, Jintao Bai, 李莉 Li Li +2 more

We investigate theoretically two-photon absorption spectroscopy modified by a control field in a confined Y-type four-level system. Dicke-narrowing effect occurs both in two-photon absorption lines and the dips of transparency against two-photon absorption due to enhanced contribution of slow atoms. We also find that the suppression and the enhancement of two-photon absorption call be modified by changing the strength of the control field and the detuning of three laser fields. This control of two-photon absorption may have some applications in information processing and optical devices.

Min Yan, Edward G. Rickey, Yifu Zhu

Atomic coherence and interference in an atomic medium exhibiting electromagnetically induced transparency may lead to enhancement or suppression of nonlinear susceptibilities. Absorptive photon switching has been observed by constructive quantum interference, which is based on the enhanced third-order, nonlinear absorption in a four-level system. In a different four-level system, suppression of the two-photon absorption by destructive quantum interference has been observed. Experiments were carried out on 87Rb atoms cooled and confined in a magneto-optical trap and the experimental results agree with theoretical calculations of simple four-level model systems.

G. Fornaca, Mario Iannuzzi, ERSEO POLACCO

Constantine Mavroyannis

Jin Li-Xia, Jiahua Li, Qi Chun-Chao

We theoretically investigate the features of two-photon absorption in a coherently driven four-level atomic system with closed-loop configuration. It is found that two-photon absorption can be completely suppressed just by properly adjusting the relative phase of four coherent low-intensity driving fields and the atomic system becomes transparent against two-photon absorption. From a physical point of view, we explicitly explain these results in terms of quantum interference induced by two different two-photon excitation channels.