Title:	Threshold nonlinear absorption in Zeeman transitions
Authors:	Narayanan, Andal Hazra, Abheera Sandhya, S.N.
Issue Date:	12-Oct-2010
Publisher:	IOP Publishing Ltd.
Citation:	Journal of Physics B, 2010, Vol.43, p215502
Abstract:	We experimentally study the absorption spectroscopy from a collection of gaseous 87Rb atoms at room temperature irradiated with three fields. Two of these fields are in a pump–probe saturation absorption configuration. The third field co-propagates with the pump field. The three fields address Zeeman degenerate transitions between hyperfine levels 5S1/2, F = 1 and 5P3/2, F = 0, F = 1 around the D2 line. We find a sub-natural absorption resonance in the counter-propagating probe field for equal detunings of all three fields. This absorption arises in conjunction with the appearance of increased transmission due to electro-magnetically induced transparency in the co-propagating fields. The novel feature of this absorption is its onset only for the blue of 5P3/2, F = 0, as the laser frequency is scanned through the excited states 5P3/2, F = 0, F = 1 and F = 2. The absorption rapidly rises to near maximum values within a narrow band of frequency near 5P3/2, F = 0. Our experimental results are compared with a dressed atom model. We find the threshold absorption to be a result of coherent interaction between the dressed states of our system.
Description:	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
URI:	http://hdl.handle.net/2289/3980
ISSN:	0953-4075 1361-6455 (Online)
Alternative Location:	http://arxiv.org/abs/0906.5231 http://dx.doi.org/10.1088/0953-4075/43/21/215502
Copyright:	2010 IOP Publishing Ltd.
Appears in Collections:	Research Papers (LAMP)

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