Population inversion in a strongly driven two-level system at far-off resonance. (31st August 2017)

• Record Type: Journal Article
• Authors: Zhang, Youyuan; Lötstedt, Erik; Yamanouchi, Kaoru
• Is Part Of: Journal of physics. Volume 50:Number 18(2017:Sep. 15)
• Publication Date: 2017-08-31
• Subjects: two-level system -- strong-field excitation -- Floquet theory -- population inversion; Atoms -- Periodicals; Molecules -- Periodicals; Optics -- Periodicals; Nuclear physics -- Periodicals; 539.6
• DOI: 10.1088/1361-6455/aa8550
• Languages: English
• ISSNs: 0953-4075

Abstract

Abstract: The population transfer dynamics in a strongly driven two-level system is studied. It is shown that population inversion can be efficiently achieved when a laser pulse whose photon energy is about half of the energy separation of the two levels is turned on suddenly. This situation is realized when a neutral atom or molecule is ionized at the peak of the laser field, followed by the laser-driven population transfer among two states of an atomic or molecular ion. The mechanism of the efficient population transfer for an ion effectively exposed to a laser field with a sudden turn-on is examined by numerical calculations based on the quasi-stationary Floquet theory.