Chanu, Sapam Ranjita and Singh, Alok K and Brun, Boris and Pandey, Kanhaiya and Natarajan, Vasant (2011) Subnatural linewidth in a strongly-driven degenerate two-level system. In: Optics Communications, 284 (20). pp. 4957-4960.
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We observe linewidths below the natural linewidth for a probe laser on a degenerate two-level F -> F' transition, when the same transition is driven by a strong control laser. We take advantage of the fact that each level of the transition is made of multiple magnetic sublevels, and use the phenomenon of electromagnetically induced transparency (EIT) or absorption ( EIA) in multilevel systems. Optical pumping by the control laser redistributes the population so that only a few sublevels contribute to the probe absorption, an explanation which is verified by a density-matrix analysis of the relevant sublevels. We observe more than a factor of 3 reduction in linewidth in the D(2) line of Rb in room-temperature vapor. Such subnatural features vastly increase the scope of applications of EIT, such as high-resolution spectroscopy and tighter locking of lasers to atomic transitions, since it is not always possible to find a suitable third level. (C) 2011 Elsevier B.V. All rights reserved.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to Elsevier Science B.V.|
|Keywords:||Electromagnetically induced transparency and absorption; Subnatural resonances;Coherent control|
|Department/Centre:||Division of Physical & Mathematical Sciences > Physics|
|Date Deposited:||28 Sep 2011 11:00|
|Last Modified:||28 Sep 2011 11:00|
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