Refractive Index Of The Concept Of Biological Organization To Define And Test Methods

With in-depth research of tissue optics, basic optical parameters in radiative transfer theory can't fulfill the demands of depicting optical characteristics of biological tissues, which impel us to search for a fundamental parameter. Combine the electromagnetism theory of optics with optical characteristics of biological tissues, we define that refractive index of tissues is a complex number which can serve as a fundamental parameter and unify the optical parameters of tissues. We observe some kinds of typical tissue slices under the phase contrast microscope and analyze the influence of refractive index and thickness of slices on the contrast of phase contrast micrographs, additionally distribution of refractive index is deduced from the phase contrast micrographs. We illuminate the specific meaning of refractive index which serves as equivalent refractive index when dealt with boundary problem and average refractive index used in time-resolved model to describe the velocity of light. A new algorithm is put forward to calculate the equivalent refractive index and some kinds of biological tissues are quantificationally measured in experiment. Feasibility of measuring complex refractive index with ellipsometry is discussed and a set of experiment equipment is set up to make elementary experiment. In the last chapter of this paper, the influence of convergence angle on the light field in biological tissues and light field reflected from biological tissues are also discussed.