Title:	Light scattering from a magnetically tunable dense random medium with weak dissipation : ferrofluid
Authors:	Shalini, M. Sharma, Divya Deshpande, A.A. Mathur, Deepak Ramachandran, Hema Kumar, N.
Keywords:	Optical Phenomena Photonics
Issue Date:	Jan-2012
Publisher:	EDP Sciences /Springer
Citation:	European Physical Journal D, 2012, Vol.66, p30
Abstract:	We present a semi-phenomenological treatment of light transmission through and its reflection from a ferrofluid which we regard as a magnetically tunable system of dense random dielectric scatterers with dissipation. Partial spatial ordering is introduced by the application of a transverse magnetic field that superimposes a periodic modulation on the dielectric randomness. This causes Bragg scattering that effectively enhances the scattering due to the disorder alone, and thus reduces the elastic mean free path towards Anderson localization. A theoretical treatment, based on invariant imbedding, gives a simultaneous decrease of the transmission and the reflection without change of incident linear polarisation as the spatial order is tuned magnetically to the Bragg condition, namely the light wave vector being equal to half the Bragg vector (Q). Our experimental observations are in qualitative agreement with these results. We have also given expressions for the transit (sojourn) time of the light, and for the light energy stored in the random medium under a steady illumination. The ferrofluid thus provides an interesting physical realization of effectively a “Lossy Anderson-Bragg” (LAB) cavity with which to study the effect of interplay of the spatial disorder, partial order and the dissipation on light transport. Given current interests in the light propagation, optical limiting and the storage of light in ferrofluids, the present work seems topical.
Description:	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
URI:	http://hdl.handle.net/2289/4373
ISSN:	1434-6060 1434-6079 (Online)
Alternative Location:	http://arxiv.org/abs/1104.4169 http://dx.doi.org/10.1140/epjd/e2011-20368-8
Copyright:	2012 EDP Sciences /Springer
Appears in Collections:	Research Papers (TP)

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