A model to describe light scattering from material made of sensitized proteins

The interest for organic molecules in photonics and their use in the conception of new photonic devices, makes necessary a better understanding of their interactions with light. In particular, the modelling of these interactions is complex for biological molecules like proteins or polypeptides. The recent work of a team in our laboratory, using sensitized proteins to carry out holographic memories, has shown this interest of biological materials and the necessity to model their interaction with light. We present a theoretical electromagnetic model for such molecules. The real structure of the molecule is replaced by a theoretical aggregate of sub-wavelength spheres. A T-matrix algorithm is used to calculated the field scattered by these aggregates. The principle of this algorithm is explained. Their advantages and limitations are compared with other rigorous numerical methods used to study electromagnetism problems. The reasons, why we can model a molecule with a theoretical aggregate of spheres, are explained. The choices of the optical parameters of these aggregates are discussed. Some electromagnetic simulations of simple cases are presented in order to illustrate these choices. The experimental validation has to be done.