Title:	Higher order nonlinearities in a non-Doppler free geometry
Authors:	Narayanan, Andal Sharma, A. Preethi, T.M. Abheera, H. Ramachandran, Hema
Issue Date:	Jul-2009
Publisher:	NRC Research Press
Citation:	Canadian Journal of Physics, 2009, Vol.87, p 843-850
Abstract:	Multi-level gaseous atomic systems showing electromagnetically induced transparency (EIT) phenomenon also exhibit low light intensity nonlinear optical phenomena. This is primarily due to the supression of linear susceptibility for the probe light during EIT. Therefore under EIT, nonlinear interactions become appreciable even at very low light intensities. In particular, Kerr nonlinearity in N systems irradiated by three fields has been both experimentally and theoretically investigated. In this paper, we report an all optical observation of an absorptive three-photon resonance feature, of subnatural width, in a N level scheme of gaseous rubidium, at room temperature, in a novel geometry of three independent beams. The non-Doppler free configuration of the beam in which the absorption is seen is the first such feature reported in a beam that is not directly taking part in the transparency effect. We have demonstrated the velocity selective nature of this absorption and studied the contrast dependence on detuning from the fourth level. Density matrix calculations have been carried out for this geometry, the results of which are in qualitative agreement with the experiment.
Description:	Restricted Access.
URI:	http://hdl.handle.net/2289/5547
ISSN:	0008-4204 1208-6045(Online)
Alternative Location:	http://dx.doi.org/10.1139/P09-023
Copyright:	2009 NRC Research Press
Appears in Collections:	Research Papers (LAMP)

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