Modelling Mueller Matrix of Fluorescence Scattering and Experimental Aspects

Saha, Sudipta (2014) Modelling Mueller Matrix of Fluorescence Scattering and Experimental Aspects. Masters thesis, Indian Institute of Science Education and Research Kolkata.

PDF (MS dissertation of Sudipta Saha) Sudipta_Saha_12IP020.pdf - Submitted Version Restricted to Repository staff only Download (1MB)

Abstract

Mueller matrix is the transfer function of an optical system. Mueller matrix is usually well-de�ned and studied for transmission and elastic scattering of light from di�erent optical medium. However, in in-elastic scattering like fluorescence, Mueller matrix polarimetry is not explored much and is absent in the literature. Our present work is directed towards modelling the Mueller matrix for fluorescence scattering. The fluorescence scattering is extremely complicated and the polarisation properties of the sample cannot be determined using the usual decomposition methods (like Lu-Chipman polar decomposition). Since polar decomposition assumes sequential e�ects, it is not valid for light scattering from uorescence samples. Also, uorescence is an extremely depolarising process. The depolarisation occurs due to: (a) multiple scattering of the exciting beam, (b) intrinsic causes of depolarisation (like Brownian rotation of the fluorophores), and (c) multiple scattering of the emergent beam. In addition to the intrinsic and extrinsic causes of depolarisation, other polarisation effects such as di�erential excitation of fluorescence by orthogonal polarisation (linear and circular), and di�erential emission of fluorescence with orthogonal polarisation (linear and circular) of incident light may also occur, which add to the complexities in terms of study of the polarisation response of fluorescence samples. These two e�ects, namely, fluorescence linear/circular dichroism and linear/circularly polarised uorescence emission may exhibit for uorophores having anisotropically oriented molecular structures. In my MS project, I developed a theoretical model to describe all the contributing fluorescence polarimetry events via Mueller matrix formalism. The validity of the model is being tested on various model systems.

Actions (login required)

View Item