生物组织的折射和折射率

光在生物组织中的传播与组织的光学性质有关。光通过组织时，光强和光的偏振状态会发生变化。而折射率是组织光学用来评价组织改变光线行进方向的基本参量。本文以菲涅耳公式为理论依据，用空气一组织界面的反射率、生物组织薄膜的反射率和生物组织反射光的倔振分量，推算生物组织的折射率。

THE REFRACTIVITY AND REFRACTIVE INDEX OF BIOLOGICAL TISSUES

Tissue optics is a rapidly growing field. The light propagation and related optical properties in biological tissues are very important in many medical applications. The refractlvlty is different for the different medium and this would cause the change of the light direction. The determination of the refractivity in the biological tissues is more difficult than that in the ordinary liquids and solids. Using double - beam spectrophotometer and intergrated sphere assernbly, we have found characteristic reflectance and transmittance wavelengthes for the visceral organs of animals,normal human tissues, benign and malignant tumors, they are from 200 to 900 nm. We have calculated the refractive index n at 589. 6 nm in two cases:the refractivity of air - tissue; air - tissue membrane -glass. We have also obtained n at 632.8 nm by measuring the degree of polarization with reflection He-Ne laser light through the biological tissue.The experimental and calculated results in many individual biological tissues indicate that there are signficant distinction of optical properties between malignant and benign human tissues. We have first explored that the refractivity index of human tissues are from 1. 55 to 1.65. The research is still on going, some of interesting phenomenon will be continually found.