ABSTRACT
The study of light is one of the oldest scientific subjects. Important experiments were performed on the diffraction and interference of light by Thomas Young and Fresnel that could only be interpreted in terms of the wave theory. In 1690, Christian Huygens proposed a theory that explained light as a wave phenomenon. The wave theory received additional support from the electromagnetic theory of Maxwell, who showed that electric and magnetic fields were propagated together and that their speed was identical to the speed of light. Most of the interactions between light and biological matter as molecular media involve electronic polarization of the molecule subjected to an electric field. When the transmission of light is under consideration, however, the wave nature dominates over the particle nature. It became clear that visible light was a form of electromagnetic radiation, constituting only a small part of the electromagnetic spectrum.
