摘要
The light trajectory in an inhomogeneous medium is studied by the variation of Lagrangians L and which correspond to Fermat’s principle in the geometrical optics and the null geodesic in the metric optics,respectively.The relation between the metric coefficients of the three-dimensional space and of the four-dimensional space-time is established.The physical meaning of the equivalence and difference of both the descriptions is revealed.It is shown that Fermat’s principle is a direct result of the null geodesic.
The light trajectory in an inhomogeneous medium is studied by the variation of Lagrangians L and which correspond to Fermat's principle in the geometrical optics and the null geodesic in the metric optics,respectively.The relation between the metric coefficients of the three-dimensional space and of the four-dimensional space-time is established.The physical meaning of the equivalence and difference of both the descriptions is revealed.It is shown that Fermat's principle is a direct result of the null geodesic.
基金
Project supported by the National Natural Science Foundation of China
National Hi-Tech(863-416)Foundation of China.
